chore: sqlstore cleanup (#60415)

* chore: remove unused test helper from sqlstore

TimeNow() is no longer used in any tests in this package.

* chore: move sqlstore.SQLBuilder to the infra/db package

This required some minor refactoring; we need to be a little more explicit about passing around the dialect and engine. On the other hand, that's a few fewer uses of the `dialect` global constant!

* chore: move UserDeletions into the only package using it

* cleanup around moving sqlbuilder

* remove dialect and sqlog global vars

* rename userDeletions to serviceAccountDeletions

pkg/infra/db/db.go

@@ -23,13 +23,11 @@ type DB interface {
 }
 
 type Session = sqlstore.DBSession
-type SQLBuilder = sqlstore.SQLBuilder
 type InitTestDBOpt = sqlstore.InitTestDBOpt
 
 var InitTestDB = sqlstore.InitTestDB
 var InitTestDBwithCfg = sqlstore.InitTestDBWithCfg
 var ProvideService = sqlstore.ProvideService
-var NewSqlBuilder = sqlstore.NewSqlBuilder
 
 func IsTestDbSQLite() bool {
 	if db, present := os.LookupEnv("GRAFANA_TEST_DB"); !present || db == "sqlite" {