Beautify our HomePage

[Blatzheim]

DEP: Everything else really...
AC:

• Add a Background for our HomePage
• In the student view, please highlight (hervorheben) the "My Lectures" section, so that it subtly jumps at you.

Hint:Please check back with me for the background image.

[Jasperhino]

@simonstadlinger has already proposed some more detailed stories for the homepage. Please check back with him.