OR-555 Remove duplicate import of bootstrap
OR-555 Add i18n strings
OR-555 Add Jade templates and update Less file
OR-555 Add a new module in esn app : esn.user-notification

Add tests for the directive.
Merge pull request #435 in OR/rse from ~RPIGNOLET/rse:OR-555 to master

* commit '1ea1d2c163bae61d18d77576bffdf976349cf02c':
  OR-555 Add a new module in esn app : esn.user-notification
  OR-555 Add Jade templates and update Less file
  OR-555 Add i18n strings
  OR-555 Remove duplicate import of bootstrap