Missing intermediate commits with good comments....

DRF:
	Updated permission check for Annotation (compatibility with v3.*) using PermissionClass
	Added a TTPAuthentication class (adim_ttp.authentication.TTPAuthentication) so api call can be done without user token

AnObj Manager:
	Updated the properties panel for TTP shared object: the link for editing the object in the distant service is more visible

The TTP permission classes are bulit from settings, no need for hardcoding.

TSD ...

Note: there is no user interface for editing the owners list.
It is supposed to be done through the API (to be done)

Added tabs for 'edit' or 'review' mode. 
The Django view checks if the user may view
shared annotations for the anobj. The layout
react accordingly.

AnObj sharing and permission at Backend level
AnObjMgr in FrontEnd allow editing of the sharing
properties. Is able to liste shared AnObj

Functions for Thumbnail creation and borders are 
now in adim_app.utils

Thumbnail creation and border are called at view
level from adim_app (no more in models)

Thumbnail size in settings, no more hardcoded

Image and thumbnail URLs are now seen as
"sub pages" of the annotable 

image     .../<anobj_uuid>/image/
thumbnail .../<anobj_uuid>/thumb/