added missing documentation for mysql server and also added a section conserning mysql in the installation guide.

Removed auto-generated OSX files. Added comments with todo on whats missing. fixed the button hyperlinks and action.

added the possibility to login with email instead of username. fixed the login and registration. still minor issue with the encrypted password never matching the correct inserted one.

added like predefined sql code is saved in data.sql during dev due to if roles table is empty, the app crashes. made a major change in stylesheet when it comes to login. fixed footer.