Create doc page outlining Redis and Valkey compatibility

[madolson]

We should have a page that at least outlines:

1. What version of Redis we are compatible with. (7.2.4) and what version we are not compatible with.
2. That we have redis_version field that is pegged at 7.2.4 with a valkey field that changes over time
3. That Lua can support either redis.function or sever.function
4. We support but RedisModule_* and ValkeyModule_* APIs.