chore: remove sqlstore & mockstore dependencies from (most) packages (#57087)

* chore: add alias for InitTestDB and Session

Adds an alias for the sqlstore InitTestDB and Session, and updates tests using these to reduce dependencies on the sqlstore.Store.

* next pass of removing sqlstore imports
* last little bit
* remove mockstore where possible

pkg/services/userauth/userauthimpl/userauth.go

@@ -3,7 +3,7 @@ package userauthimpl
 import (
 	"context"
 
-	"github.com/grafana/grafana/pkg/services/sqlstore/db"
+	"github.com/grafana/grafana/pkg/infra/db"
 	"github.com/grafana/grafana/pkg/services/userauth"
 )