* Move scope type vars to testutil package
* Expose parts of state historian for use in annotation backend
* Implement Loki ASH Annotation store
This store will only implement the `Get` method of a RepositoryImpl since alert state history
writes to Loki elsewhere.
* Use interface for Loki HTTP Client
* Add tests for Loki ASH Annotation store
* Add missing test
* Fix lint
* Organize tests
* Add filter tests
* Improve tests
* Move filter logic into outer function
* Fix lint
* Add comment
* Fix tests
* Fix lint
* Rename historian store + refactor
* Cleanup historian store
* Fix tests
* Minor cleanup
* Use new `ShouldRecordAnnotation` filter
* Fix logic and add tests for this check
* Fix typos, remove unused variables, `< 1` -> `== 0`
* More closely mimic RBAC filter from xorm to ensure correct logic
* Move off weaveworks client
* Address PR comments
* Add Loki historian store stub
* Add composite store
* Use composite store if Loki historian enabled
* Split store interface into read/write
* Make composite + historian stores read only
* Use variadic constructor for composite
* Modify Loki store enable logic
* Use dskit.concurrency.ForEachJob for parallelism
