update AUTH as now we have ACL commands

[Niennienzz]

• Update AUTH command docs.
• The password-only format checks the password set by --requirepass.
• The user & password format checks ACL users.

[kostasrim]

@Niennienzz I will ping once I make the small changes and we will adjust the docs. I am making a comment here so we don't forget. Thank you for opening this 🙏

[Niennienzz]

@kostasrim for sure, thanks!

[romange]

@kostasrim we should also introduce a dedicated page of how to set up ACL settings under https://www.dragonflydb.io/docs/managing-dragonfly
a tutorial, step by step guide for someone who installs our debian package. It should mention all the changes to config files, where to put the aclfile etc.

[romange]

For example, the recommended placement for the aclfile should not be under /etc dir and it should be under /var/lib/dragonfly/.
we should explain that /etc/ is not accesible by dragonfly process but it could be used as a readonly (protected) aclfile location and if someone wants to override the behavior to point them to the systemd dragonfly.service file etc. Basically explaining all the "default" steps and caveats

[kostasrim]

@romange 100%, I will take care of it

[kostasrim]

p.s. I am baking in some minor changes that will bring us on par with Redis behaviour (for requirepass and auth) -- I already submitted the PR's I just need to make a few small modifications and we should be good to go.

p.s.2. I will do the docs ocne I merge these.