[Feature](supernova): Adjust fetch from Alertmanager to include initial filters

[majewsky]

Priority

(Medium) I'm annoyed but I'll live

Is your feature request related to a problem?

Loading all alerts from Alertmanager causes excessive memory usage and increases the time for the Alertmanager API to return a result. The UI should use the filtering capability that's present in the Alertmanager API to only request what it actually needs.

This does not necessarily need to be done for every single filter change, but e.g. support_group is something that most people do not change, so instead of GET /api/v2/alerts, you could GET /api/v2/alerts?filter=support_group%3Dfoobar once the support group foobar has been selected either automatically or manually.

Additional context.

No response

Reference Issues

No response