Add a 'status' action to detect if some migration scripts are pending

- add application 'ALL' to bin/horde-db-migrate to be able
to run an action different than up ( as status ) for all
apps
- add 'status' action to bin/horde-db-migrate to check
if some migrations are missing
- add 'status' action to bin/horde-db-migrate-component
to check if some migrations are missing