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

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.

Start with ApplicationManifestUtils, especially asList, asListOfString, and toApplicationManifest, using the supplied manifest as the reproduction case. Trace how service binding parameters are converted and verify that nested parameter mappings parse without the reported ClassCastException while preserving their values.