Humanize invalid login error message and downcase authentication keys

[baarkerlounger]

Re-opening this #4834 on main since development of the v5 rc branch seems to have stalled.

[baarkerlounger]

@carlosantoniodasilva or @tegon would you be willing to merge this? It's just error string updates and was previously merged into the V5 RC branch.

[carlosantoniodasilva]

If it was/is in the v5 branch, it's because it's technically "breaking" in some way and it's hard to update those things in patch/minor versions sometimes.

That said, v5 isn't dead, we will release a major version at some point, there's just some other things that need to be taken care of first.

I'll keep this one open and assigned to me to circle back on it, thanks.

[baarkerlounger]

@carlosantoniodasilva this is purely a string change for error message (correct capitalisation of words) so I don't think it's a breaking change, I think it was just merged into v5 rather than main in the expectation that that was the primary development branch at the time?

Appreciate you looking at it though!

[baarkerlounger]

@marivaldo thanks for reviewing. Have made the suggested changes.

[baarkerlounger]

@carlosantoniodasilva @marivaldo rebased this on the latest changes, could you take a look and enable CI?