Add support for specifying a custom Logical ID for the AWS::AppSync::GraphQLApi resource

[manwaring]

Exploring a possible solution to #617 by supporting a parameter to prefix the AWS::AppSync::GraphQLApi Logical ID (instead of only supporting GraphQlApi)

• Update plugin schema/types
• Add optional override property
• Add unit tests
• Confirm if approach is acceptable to library creator/maintainer

[bboure]

Is this necessary?

Unless I am missing something, we probably could get away with having a
apiLogicalId that overrides getLogicalId.

The rest of the logical ids should be safe. i.e. They might be re-created but they are not stateful.

That would simplify everything.

[bboure]

As per my other comment, could this be named apiLogicalId?

[bboure]

Thank you @manwaring

Could we also add documentation of when and how to use it?

[sid88in]

Closing this in its current form — as noted in review, it makes far more logical IDs
configurable than necessary. Only the AWS::AppSync::GraphQLApi logical ID is stateful
(changing it replaces the API); the schema/data-source/resolver/log-group IDs can be
recreated harmlessly, so they don't need to be overridable.

The useful, minimal version of this is a single optional apiLogicalId that overrides just
getApiLogicalId() — handy for migrating an existing CFN-managed API into the plugin without
forcing a replacement. If anyone wants that, I've opened a scoped good first issue for it.

Thanks for the contribution and the prod on the use case!