feat(blooms): Add task timining and sizing metrics (backport k229)

[loki-gh-app]

Backport 79cccfd from #15032

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What this PR does / why we need it:

This PR adds observability around the time it takes tasks to complete as well as metrics for the amount of data the tasks will process.

We also refactor the planning strategy factory from a function into a struct. This is needed so we don't need to recreate the metrics.

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR