Change the homepage banner picture

[thepinebook]

During our meeting 15 Feb we decided that the background image once logged in has to be replaced with a higher quality one.

[C4ptainCrunch]

To be more precise, we said that the banner on the homepage looks a lot like one of the official websites of ULB (probably the auth page) and we should try to change it to differentiate better.

Does someone have an idea of something that keeps the "feeling" that this is FOR the ULB (opposed to studocu for example) but still make it clear that it's for BY the ULB ?

[C4ptainCrunch]

Relates to #302