Chore: Start annotations app (#113018)

* annotation legacy store with api server, read only

* Add a feature flag for annotations app

* implement list filters

* annotations are not addressable by ID for read operations

* fix registry apps test

* add ownership for an app

* disable linter

* typo, of course

* fix go workspace

* update workspace

* copy annotation app in dockerfile

* update workspace

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Co-authored-by: Tania B. <10127682+undef1nd@users.noreply.github.com>

.github/CODEOWNERS

@@ -98,6 +98,7 @@
 /apps/correlations @grafana/datapro
 /apps/example/ @grafana/grafana-app-platform-squad
 /apps/logsdrilldown/ @grafana/observability-logs
+/apps/annotation/ @grafana/grafana-backend-services-squad
 /pkg/api/ @grafana/grafana-backend-group
 /pkg/apis/ @grafana/grafana-app-platform-squad
 /pkg/apis/query @grafana/grafana-datasources-core-services