Docs: Add compactor.max-compaction-time to MimirCompactorHasNotSuccessfullyRunCompaction runbook

[56quarters]

In some situations, the correct way to resolve a MimirCompactorHasNotSuccessfullyRunCompaction alert is to set the compactor.max-compaction-time flag so that only a smaller (several hours) amount of time is spent during the compaction cycle for a single tenant. Per the docs for the flag:

This can help in multi-tenant environments to avoid single tenant using
all compaction time, but also in single-tenant environments to force new
discovery of blocks more often

One instance of the alert triggering was a large number of "backfilled" blocks for a single tenant, monopolizing compactor time.

[pracucci]

I would argue we should set a reasonable default for that flag. For example, there's no real performance impact (with regards to object storage API calls and overhead in compaction) if we set it to something between 1h and 2h, but would be a better default.

[osg-grafana]

Removing from Docs Team remit because the documentation is operational in nature, and runbooks are maintained by engineers.