Monitor availability over time

[pvgenuchten]

The link liveliness checker implements the checking of links in metadata and the storage of the results of these checks in the SWR database.

To provide useful status info and monitoring, the liveliness checker should be operationalised as a process and the results need to be translated to end user visualisation, for now through the catalogue UI.

Definition of Done

• [x] Decisions on the design of the operational workflow and management (include in scheduled task, delete outdated history records) and monitoring (e.g. desired visualisation)
• [x] Operationalisation of the liveliness checker as part of the workflow (backend)
• [x] Implement a call that can be used to retrieve/translate the status of a link for monitoring
• [x] Adapt UI to show monitoring results

[roblokers]

Issue description updated based on a discussion with @pvgenuchten