Input JSON path from HTTP - bypass certificat verification

## What ?
Bypass certificate verification on a Input JSON path from HTTP

## Why?
Complexity of import certificat on JVM keystore, specially on docker/ kubernetes environnement

Like on curl command with "-- insecure" / "-k" option.

* Graylog Version: 2.5
* Elasticsearch Version: 6.7

`

2019-11-27 15:05:21,372 INFO : org.graylog2.inputs.InputStateListener - Input [JSON path from HTTP API/5dde8c29bd1a3a0010f2cf99] is now STARTING
  | 2019-11-27 15:05:21,372 INFO : org.graylog2.inputs.InputStateListener - Input [JSON path from HTTP API/5dde8c29bd1a3a0010f2cf99] is now RUNNING
  | 2019-11-27 15:05:21,446 ERROR: org.graylog2.inputs.transports.HttpPollTransport - Could not fetch HTTP resource at https://open.ebu.ch/api/
  | javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
  | at sun.security.ssl.Alerts.getSSLException(Alerts.java:192) ~[?:1.8.0_212]
  | at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1946) ~[?:1.8.0_212]
  | at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:316) ~[?:1.8.0_212]
  | at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:310) ~[?:1.8.0_212]
  | at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1639) ~[?:1.8.0_212]
  | at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:223) ~[?:1.8.0_212]
  | at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037) ~[?:1.8.0_212]
  | at sun.security.ssl.Handshaker.process_record(Handshaker.java:965) ~[?:1.8.0_212]
  | at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1064) ~[?:1.8.0_212]
  | at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1367) ~[?:1.8.0_212]
  | at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1395) ~[?:1.8.0_212]
  | at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1379) ~[?:1.8.0_212]
  | at okhttp3.internal.connection.RealConnection.connectTls(RealConnection.java:318) ~[graylog.jar:?]
  | at okhttp3.internal.connection.RealConnection.establishProtocol(RealConnection.java:282) ~[graylog.jar:?]
  | at okhttp3.internal.connection.RealConnection.connect(RealConnection.java:167) ~[graylog.jar:?]
  | at okhttp3.internal.connection.StreamAllocation.findConnection(StreamAllocation.java:257) ~[graylog.jar:?]
  | at okhttp3.internal.connection.StreamAllocation.findHealthyConnection(StreamAllocation.java:135) ~[graylog.jar:?]
  | at okhttp3.internal.connection.StreamAllocation.newStream(StreamAllocation.java:114) ~[graylog.jar:?]
  | at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:42) ~[graylog.jar:?]
  | at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) ~[graylog.jar:?]
  | at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) ~[graylog.jar:?]
  | at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93) ~[graylog.jar:?]
  | at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) ~[graylog.jar:?]
  | at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) ~[graylog.jar:?]
  | at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93) ~[graylog.jar:?]
  | at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) ~[graylog.jar:?]
  | at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:126) ~[graylog.jar:?]
  | at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) ~[graylog.jar:?]
  | at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) ~[graylog.jar:?]
  | at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:200) ~[graylog.jar:?]
  | at okhttp3.RealCall.execute(RealCall.java:77) ~[graylog.jar:?]
  | at org.graylog2.inputs.transports.HttpPollTransport.lambda$doLaunch$1(HttpPollTransport.java:163) ~[graylog.jar:?]
  | at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_212]
  | at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [?:1.8.0_212]
  | at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [?:1.8.0_212]
  | at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [?:1.8.0_212]
  | at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_212]
  | at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_212]
  | at java.lang.Thread.run(Thread.java:748) [?:1.8.0_212]
  | Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
  | at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:397) ~[?:1.8.0_212]
  | at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302) ~[?:1.8.0_212]
  | at sun.security.validator.Validator.validate(Validator.java:262) ~[?:1.8.0_212]
  | at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324) ~[?:1.8.0_212]
  | at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229) ~[?:1.8.0_212]
  | at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124) ~[?:1.8.0_212]
  | at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1621) ~[?:1.8.0_212]
  | ... 34 more
  | Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
  | at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141) ~[?:1.8.0_212]
  | at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126) ~[?:1.8.0_212]
  | at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280) ~[?:1.8.0_212]
  | at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:392) ~[?:1.8.0_212]
  | at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302) ~[?:1.8.0_212]
  | at sun.security.validator.Validator.validate(Validator.java:262) ~[?:1.8.0_212]
  | at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324) ~[?:1.8.0_212]
  | at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229) ~[?:1.8.0_212]
  | at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124) ~[?:1.8.0_212]
  | at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1621) ~[?:1.8.0_212]
  | ... 34 more

`