Various fixes

[FunConclusion2661]

• Fix bug where you cannot log in if your username is over 32 characters (possible when site.username_max_length is changed)
• Fix for attributes on the user preferences template so the labels are labelling the correct element
• Fix adding admin user instructions in readme (python3 scripts/admins.py --add → ./thoat.py admin add)
• Make the Make docker-npm recipe a .PHONY target

Let me know if I should split this into multiple PRs.

[Polsaker]

good stuff