Allow multiple non modifiable subresource with the same primary key

[deepanjan90]

Is your feature request related to a problem? Please describe.
In some cases there are subresource which are attached to the parent as list, i.e supporting multiple entries. Often times the api of a provider supports duplicate entries of these as they are unmodifiable.

Currently this is not supported by gyro. Results in a exception similar to

Unexpected error: java.lang.IllegalArgumentException: Multiple entries with same key: Optional[]=device  and Optional[]=device 
	at com.google.common.collect.ImmutableMap.checkNoConflict(ImmutableMap.java:190)
	at com.google.common.collect.RegularImmutableMap.checkNoConflictInKeyBucket(RegularImmutableMap.java:109)
	at com.google.common.collect.RegularImmutableMap.fromEntryArray(RegularImmutableMap.java:95)
	at com.google.common.collect.ImmutableMap$Builder.build(ImmutableMap.java:373)
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:503)
	at gyro.core.scope.NodeEvaluator.lambda$copy$37(NodeEvaluator.java:571)
	at java.util.Optional.map(Optional.java:215)
	at gyro.core.scope.NodeEvaluator.copy(NodeEvaluator.java:571)
	at gyro.core.scope.NodeEvaluator.lambda$copy$38(NodeEvaluator.java:574)
	at java.util.stream.Streams$StreamBuilderImpl.forEachRemaining(Streams.java:419)
	at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580)
	at gyro.core.scope.NodeEvaluator.copy(NodeEvaluator.java:574)
	at gyro.core.scope.NodeEvaluator.lambda$copy$38(NodeEvaluator.java:574)
	at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
	at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580)
	at gyro.core.scope.NodeEvaluator.copy(NodeEvaluator.java:574)
	at gyro.core.scope.NodeEvaluator.lambda$visitResource$35(NodeEvaluator.java:525)
	at java.util.Optional.ifPresent(Optional.java:159)
	at gyro.core.scope.NodeEvaluator.visitResource(NodeEvaluator.java:525)
	at gyro.core.scope.NodeEvaluator.visitResource(NodeEvaluator.java:81)
	at gyro.lang.ast.block.ResourceNode.accept(ResourceNode.java:55)
	at gyro.lang.ast.NodeVisitor.visit(NodeVisitor.java:37)
	at gyro.core.scope.NodeEvaluator.lambda$evaluateBody$31(NodeEvaluator.java:341)
	at gyro.core.scope.Defer.execute(Defer.java:50)
	at gyro.core.scope.NodeEvaluator.evaluateBody(NodeEvaluator.java:341)
	at gyro.core.scope.NodeEvaluator.visitFile(NodeEvaluator.java:424)
	at gyro.core.scope.NodeEvaluator.visitFile(NodeEvaluator.java:81)
	at gyro.lang.ast.block.FileNode.accept(FileNode.java:32)
	at gyro.lang.ast.NodeVisitor.visit(NodeVisitor.java:37)
	at gyro.core.scope.NodeEvaluator.lambda$evaluateBody$31(NodeEvaluator.java:341)
	at gyro.core.scope.Defer.execute(Defer.java:50)
	at gyro.core.scope.NodeEvaluator.evaluateBody(NodeEvaluator.java:341)
	at gyro.core.scope.NodeEvaluator.evaluate(NodeEvaluator.java:325)
	at gyro.core.scope.RootScope.evaluate(RootScope.java:443)
	at gyro.core.command.AbstractConfigCommand.doExecute(AbstractConfigCommand.java:179)
	at gyro.core.command.AbstractCommand.execute(AbstractCommand.java:75)
	at gyro.cli.Gyro.run(Gyro.java:205)
	at gyro.cli.Gyro.main(Gyro.java:82)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
	at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)

Describe the solution you'd like
Gyro should support duplicate primary keys for subresources where subresources are unmodifiable. Have a way to for gyro to know that these subresources are unmodifiable and allow duplicate primary keys for these.

Describe alternatives you've considered

• Have another abstract class FinalDiffable that extends Diffable. Gyro ignores checking for duplicate keys of instances of FinalDiffable.

• let gyro go through all the fields in the subresource and find if none of the fields have the @Updatable annotation then consider the subresource as unmodifiable