Add experimental read write deployment mode support to Mimir

[pracucci]

What this PR does

In this PR I'm introducing the targets to run the read-write deployment mode, as described in #2749. The Alertmanager is the only component currently excluded and will be addressed in a separate PR. Integration tests, support for dashboards and alerts, and documetation will be covered by follow up PRs.

I've also introduced a local development environment to easily run it.

In details, as separate commits:

• Added read, write and backend targets
• Added unit test cases
• Added local development environment

Which issue(s) this PR fixes or relates to

Part of #2749

Checklist

• [ ] Tests updated
• [ ] Documentation added
• [x] CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[github-actions[bot]]

Helm <> Jsonnet Diff

:warning: A difference was detected between the Helm chart and the Jsonnet library.

1. Use make check-helm-jsonnet-diff to reproduce the output locally.
2. This test is experimental while we gather feedback about its usefulness.
3. It does not block your PR from being merged, but we would appreciate you trying to keep feature parity between the Helm chart and Jsonnet library if possible.

If you get stuck on this step and the Mimir maintainers aren't able to help, feel free to merge without making this step pass and tag @Logiraptor so the Mimir maintainers can gather feedback later.

Please see the contribution docs here for more info.

Expand to see the output

Output of https://github.com/grafana/mimir/actions/runs/2875609478

Warning: policy/v1beta1 PodDisruptionBudget is deprecated in v1.21+, unavailable in v1.25+; use policy/v1 PodDisruptionBudget
diff -r -u -N scratch/./helm/07-config/query-scheduler-MimirConfig.yml scratch/./jsonnet/08-config/query-scheduler-MimirConfig.yml
--- scratch/./helm/07-config/query-scheduler-MimirConfig.yml	2022-08-17 13:22:10.774444866 +0000
+++ scratch/./jsonnet/08-config/query-scheduler-MimirConfig.yml	2022-08-17 13:22:18.314871285 +0000
@@ -498,7 +498,7 @@
       min_ready_duration: 15s (default)
       observe_period: 0s (default)
       replication_factor: 3 (default)
-      tokens_file_path: /data/tokens
+      tokens_file_path: ' (default)'
       zone_awareness_enabled: false (default)
     tsdb_config_update_period: 15s (default)
   ingester_client:
@@ -881,7 +881,7 @@
           secondary: ' (default)'
         store: memberlist (default)
       replication_factor: 3 (default)
-      tokens_file_path: /data/tokens
+      tokens_file_path: ' (default)'
       unregister_on_shutdown: true (default)
       wait_stability_max_duration: 5m0s (default)
       zone_awareness_enabled: false (default)