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/preference/prefimpl/pref.go

@@ -5,9 +5,9 @@ import (
 	"errors"
 	"time"
 
+	"github.com/grafana/grafana/pkg/infra/db"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	pref "github.com/grafana/grafana/pkg/services/preference"
-	"github.com/grafana/grafana/pkg/services/sqlstore/db"
 	"github.com/grafana/grafana/pkg/setting"
 )