Feature request: Add support for arbitrary parameters when binding services via manifest.yml

从 ApplicationManifestUtils 开始，重点查看 asList、asListOfString 和 toApplicationManifest，并使用提供的 manifest 作为复现用例。跟踪 service binding 参数的转换方式，并验证嵌套参数映射能够在不出现所报告的 ClassCastException 的情况下完成解析，同时保留其值。

Hello,

I want to report this error when we push an app manifest with binding parameters. It seems that the manifest yaml doesn't get parsed correctly because the format is not supported

java.lang.ClassCastException: Cannot cast java.util.LinkedHashMap to java.lang.String
	at java.lang.Class.cast(Class.java:3369)
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
	at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
	at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
	at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:485)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils.lambda$asList$2(ApplicationManifestUtils.java:160)
	at java.util.Optional.ifPresent(Optional.java:159)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils.as(ApplicationManifestUtils.java:131)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils.asList(ApplicationManifestUtils.java:157)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils.asListOfString(ApplicationManifestUtils.java:164)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils.toApplicationManifest(ApplicationManifestUtils.java:346)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils.lambda$doRead$9(ApplicationManifestUtils.java:236)
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
	at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:566)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils.doRead(ApplicationManifestUtils.java:240)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils.read(ApplicationManifestUtils.java:73)
	at org.cloudfoundry.operations.applications.ApplicationManifestUtils$read.call(Unknown Source)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)

Manifest format:

--- 
applications: 
- name: my-app
  services:
  - name: my-service1
    parameters: 
      foo: bar
      herp: derp
  - name: my-service2
    parameters: 
      foo: bar

  For more details on the binding params please read: https://docs.cloudfoundry.org/devguide/services/application-binding.html#-binding-with-application-manifest

Best regards.