Basic custom home controller

Summary: Custom users and public home controller for c4science

Test Plan:

• Go to / when not logged in
• Nice home page !
• Go to / when logged in
• Nice home page too !

• Go to / when not logged in
• Nice home page !
• Go to / when logged in
• Nice home page too !

Maniphest Tasks: T1245, T1072, T1071, T761

Differential Revision: https://c4science.ch/D143