deploy: Add missing setting to archipelago.conf

Add recently introduced 'BLKTAB_ENABLED' setting to archipelago.conf.
astakos: Improve project notification emails
astakos: Validate input of project application

Check max values and update tests accordingly.
astakos: Move checks from api to project functions

Collect all validation checks in functions.submit_application; also
improve name check.
cyclades: Validate VM metadata on create/update

* Check for VM max metadata items when updating/creating a single item.
* Check the length of metadata items when updating a server.