[FEATURE] Add example of ignoring certificate validation when using local docker container

Is your feature request related to a problem?

Docker compose launches OpenSearch using https with self signed cert. Example code only shows how to specify a trust store but didn't show how to disable the verification on client side (for local testing).

• Demo cert from https://github.com/opensearch-project/security/blob/207cfcc379ffd4127e32b9fdfdd75ea394b48d0e/tools/install_demo_configuration.sh#L201
• Example error

javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

	at org.opensearch.client.RestClient.extractAndWrapCause(RestClient.java:902)
	at org.opensearch.client.RestClient.performRequest(RestClient.java:301)
	at org.opensearch.client.RestClient.performRequest(RestClient.java:289)
	at org.opensearch.client.RestHighLevelClient.internalPerformRequest(RestHighLevelClient.java:1762)
	at org.opensearch.client.RestHighLevelClient.performRequest(RestHighLevelClient.java:1745)
	at org.opensearch.client.RestHighLevelClient.performRequestAndParseEntity(RestHighLevelClient.java:1709)
	at org.opensearch.client.IndicesClient.create(IndicesClient.java:160)

What solution would you like?

Tell people how to disable the certificate verification (if they know what they are doing) https://opensearch.org/docs/latest/clients/java/. I am not sure if there is a doc repo Maybe I should create the issue in https://github.com/opensearch-project/documentation-website/issues instead?

        RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(HttpHost.create("https://localhost:9200"))
                .setHttpClientConfigCallback((c) -> {
                    // Disable cert verification
                    // https://stackoverflow.com/questions/2703161/how-to-ignore-ssl-certificate-errors-in-apache-httpclient-4-0
                    // because default uses a demo cert from https://github.com/opensearch-project/security/blob/207cfcc379ffd4127e32b9fdfdd75ea394b48d0e/tools/install_demo_configuration.sh#L201
                    try {
                        c.setSSLContext(new SSLContextBuilder().loadTrustMaterial(null, TrustAllStrategy.INSTANCE).build())
                                .setSSLHostnameVerifier(new NoopHostnameVerifier());
                    } catch (NoSuchAlgorithmException | KeyManagementException | KeyStoreException e) {
                        throw new RuntimeException(e);
                    }
                    return c.setDefaultCredentialsProvider(credentialsProvider);
                }));

What alternatives have you considered?

Alternatives requires more commands to type, rebuild container etc.

• Provide instruction on how to generating new self signed cert
• Disable security https://opensearch.org/docs/latest/security-plugin/configuration/disable/#docker

Do you have any additional context?

N/A

Start with the Java client documentation at https://opensearch.org/docs/latest/clients/java/ and review the supplied RestHighLevelClient example for local Docker connections. Document how to disable certificate and hostname verification for self-signed local certificates, with the existing alternatives and local-testing context, and make the example clear when the documentation is updated.