feat(composition): Relax @tag directive definition validation

[trevor-scheer]

Users should be allowed to provide a @tag directive definition which is a "subset" of the spec'ed @tag directive. i.e. the validation should permit leaving out repeatable or any of the directive locations. But it should continue to enforce the non-null arg name: String!.

This is in response to a lack of repeatable support in Kotlin, but also seems like a reasonable pattern to follow for core directives going forward.