OR-797 Correct user notification category switch
OR-797 GET `/api/user/notifications` return notification not
acknowledged
OR-797 Set `acknowledged` to `true` for accepted/declined notification
OR-797 Fix user notification counter

Increase the counter by 1 and launch background refresh timer when a
`usernotification:created` is received from the websocket.
OR-797 Fix negative counter
OR-797 Hide accept and decline button when request success

When the user accept or decline the invitation, buttons is replaced by a
text which tell him he was added to the community or he decline the
invitation.
OR-797 Reduce padding to show bottom border
OR-797 Handle `community:join` user notification category
OR-797 Fix frontend tests
Merge pull request #578 in OR/rse from ~RPIGNOLET/rse:OR-797 to master

* commit 'e609478c5b52af42c5cf477cb7bd327b9337b551':
  OR-797 Fix frontend tests
  OR-797 Handle `community:join` user notification category
  OR-797 Reduce padding to show bottom border
  OR-797 Hide accept and decline button when request success
  OR-797 Fix negative counter
  OR-797 Fix user notification counter
  OR-797 Set `acknowledged` to `true` for accepted/declined notification
  OR-797 GET `/api/user/notifications` return notification not acknowledged
  OR-797 Correct user notification category switch