Move the http interface in a new plugin architecture for http views
add a plugin to return hardcoded directory results to aastra phones
Merge branch 'frontends' into stevedore-2

Conflicts:
	xivo_dird/main.py
add aastra_view to http_views
add an endpoint to the lookup url of aastra

the app.route decorator uses the function name as endpoint and will use the same lookup
function for all "lookup" function that are decorated by app.route without an endpoint