OR-554 Timestamp is now on the same line than the title in Firefox
OR-554 Add some padding to have better display
OR-554 Fix decision for acknowledged notification

Now when switching page in user notification popover, the decision is
kept for community membership invitation.
OR-554 Fix user notification layout

* User notification use all the height.
* Reduce `padding-top` and `padding-bottom`.
OR-554 Add missing `.esn-panel` class in two templates
Merge pull request #660 in OR/rse from ~RPIGNOLET/rse:OR-554 to master

* commit '3ae8fbff0194b7f0c6144f9f3aacd69802f462da':
  OR-554 Add missing `.esn-panel` class in two templates
  OR-554 Fix user notification layout
  OR-554 Fix decision for acknowledged notification
  OR-554 Add some padding to have better display
  OR-554 Timestamp is now on the same line than the title in Firefox