[Redis] Option to authenticate using name and password

[okiedork]

Hi 👋

I'm using Stash with the Redis driver. As far as I understood from the docs, only a password option can be set. This will enable access as the default user, with a password.

Redis 6 and 7 (as far as I know) allow fine grained ACL rules. Example: I can disable the default user and use another username to authenticate.

My request is to add one more option, user or username, that can be used together with password to authenticate.

Possibly relevant docs on phpredis repo: link.

[okiedork]

I'm working on a PR for this feature.