Rebuild Authentication

[jannaahs]

The used library was last updated 5 years ago and is not developed anymore.

Also middlewares can be used.

[knoxfighter]

• Login
• Redirect after login
• Logout
• Fix error after Logout
• Check login status with middleware
• Fix websocket connection
• List users
• Add user
• Remove user
• Change password
• Error messaging (All errors are just moved, but nothing is printed (backendside))
• Update readme/wiki and dockerfiles to use sqfile.db instead of auth.leveldb
• When the cookieEncryptionKey is changed all current cookies are invalid and a login is not longer possible (Error 500)