feat: Implement owned streams calculation using Partition Ring

[benclive]

What this PR does / why we need it:
Implements recalculateOwnedStreams logic using the partition ring.

• The stream logic is unchanged but I isolated the ring-based logic into new components ("strategies") depending on the ring in use.
• Also fixed a bug with the partition ring not initialising properly.

Which issue(s) this PR fixes:
Fixes https://github.com/grafana/loki-private/issues/1117

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
• For Helm chart changes bump the Helm chart version in production/helm/loki/Chart.yaml and update production/helm/loki/CHANGELOG.md and production/helm/loki/README.md. Example PR
• 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

[grobinson-grafana]

LGTM, a couple of nits!