Kan doc update bis

Modifications done on API doc: 
A) Bund logo appears clearly on mobile
B) Footer adapted
C) New chapter "About Geoadmin API"
D) New chapter "API uptime status"

Note: for these purposes, I had to modify the template theme provided by Sphinx Read The Docs (https://github.com/snide/sphinx_rtd_theme). It can be found in our buildout/local_eggs folder.

[Test Link](http://mf-chsdi3.dev.bgdi.ch/kan_doc_update_bis/)

Do not hesitate to comment/feedback.