removed 'regular' filter from API task list

add service monitor to monitoring page

add service monitor to monitoring page

add service monitor to monitoring page

monitor endpoint and database change

https://support.astron.nl/jira/browse/SDC-475

(and to read serializer, not yet to write serializer)

added /atdb/tasks/?predecessor__status=defining filter options to REST API

add 'resume' filter (hold/start)
removed 'defining' filters
added nicer 'Filter' button

- adding job table
see https://support.astron.nl/jira/browse/SDC-142

- priority default to 0
- sizes to BigPositiveInteger

adding status buttons to GUI

skeleton for 'get_size' endpoint

- skip -> resume
- added task.metrics

This reverts merge request !1