Adding password complexity checking for local account authentication.

[ghost]

I saw the comment about the TODO for password complexity and I needed it for my server. Happy to contribute! Hope ya'll like it.

[MaxNad]

Hi @schlpr0k ,
Thank you for contributing. I really like the improvement idea.

There is one thing I would like to change before merging this into the project. The only problem I see with that current change is the lack of flexibility in the password filtering. For instance, somebody might want to force 15 chars instead of 12 or maybe require 50 chars but not complexity.

I will try to see how we could build a bit more flexibility on top of your change and merge it then.

Thanks again a lot for the contribution.