This commit removes unused language files and preserves the English sources for Crowdin. The account confirmation page has also been re-skinned with the current login/register template.
Some missing translations for 2fa were also added to the main messages file.
Sources for translations for the menus were also added.
This commit adds a password strength requirement for new users using
regular expressions.
Also adds a dismissable alert so users know how to create passwords
properly.
