OR-736 improve user invite input CSS to make it more responsive
OR-736 update texts and move error in invite user widget
OR-736 add feedback for invitations not sent
OR-736 add missing i18n entry
Merge pull request #619 in OR/rse from OR/rse-gcrosmarie:OR-736 to master

* commit 'd7ea4cefc62d571f8a497103ed5b054c23778b54':
  OR-736 add missing i18n entry
  OR-736 add feedback for invitations not sent
  OR-736 update texts and move error in invite user widget
  OR-736 improve user invite input CSS to make it more responsive