Support renaming commands

[nrvnrvn]

From amaizfinance/redis-operator#16:
Renaming commands is not supported and specifically ignored by the Redis Operator: https://github.com/nrvnrvn/redis-operator/blob/381d91fe6ec9490de5e7c29b60b5ccc19b94d00a/pkg/controller/redis/object_generator.go#L105

Can we remove this restriction? Renaming commands is quite useful and can improve security.

[nrvnrvn]

original comment:

Hi! I think it is possible. Initially I introduced this restriction to protect some essential configuration options. Excluding the rename-command was a way to protect a user from shooting their leg. On the other hand we have two options for removing this restriction:

1. allow rename-command as is
2. allow rename-command but protect some essential commands like REPLICAOF.

The first option is super easy and it will be sole user's responsibility to apply any renamings with caution.
The second option implies introducing some parsing logic and a list of excluded commands but I am not sure if it is worth spending time on it.