Register RedisModule_* APIs under the ValkeyModule_* namespace as well

[PingXie]

No description provided.

[zuiderkwast]

Duplicate of #146?

I believe it's the same intentions.

[PingXie]

I meant to use this issue to track the specific work of dual-registering the module APIs under both RM_ and VK_ namespaces. #194 is getting too big so wanted to focus on just the defines.

[PingXie]

Change of plan. #194 now contains all changes required to support a native Valkey module interface that is both source and ABI compatible with the Redis module interface.