Chore: Sql store split for legacy alerting (#52901)

Moves ~20 sqlstore methods for legacy alerting out of sqlstore (sqlstore.Store interface) and into alerting.

pkg/services/sqlstore/db/db.go

@@ -10,5 +10,6 @@ import (
 type DB interface {
 	WithTransactionalDbSession(ctx context.Context, callback sqlstore.DBTransactionFunc) error
 	WithDbSession(ctx context.Context, callback sqlstore.DBTransactionFunc) error
+	NewSession(ctx context.Context) *sqlstore.DBSession
 	GetDialect() migrator.Dialect
 }