REGISTRAR: updated invitations

- Support for more tags in invitation template.
- Updated javadoc.
- Name is now optional when sending invitation.
GUI: updated invitations

- Name is now optional when sending invitation.
Merge pull request #470 from zlamalp/registrar

REGISTRAR,GUI: updated invitations
GUI: allow to click on send request for quota change
Merge pull request #471 from zlamalp/gui

GUI: allow to click on send request for quota change