[System status] Add some service checks

Add checks if e.g. maintenance or debug mode is enabled.

changed milestone to %1.0a1

added part::frontend prio::3 type::feature + 1 deleted label

mentioned in commit 2d52cb29

mentioned in merge request !48 (merged)

mentioned in commit b5be7840

mentioned in commit c0196e1c

changed title from [System status] Show alert if maintenance_mode is enabled to [System status] Add some service checks

changed the description

closed via merge request !48 (merged)

mentioned in commit 5e9a66f8