SQLStore: Enable migration locking by default (#84983)

* Introduce new configuration for migration locking

* Remove feature toggle

* Fix test and turn it into an integration

* Fix docs

pkg/services/sqlstore/migrations/migrations_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	"github.com/go-sql-driver/mysql"
+	"github.com/golang-migrate/migrate/v4/database"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"gopkg.in/ini.v1"
@@ -69,7 +70,11 @@ func TestMigrations(t *testing.T) {
 	checkStepsAndDatabaseMatch(t, mg, expectedMigrations)
 }
 
-func TestMigrationLock(t *testing.T) {
+func TestIntegrationMigrationLock(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping integration test")
+	}
+
 	dbType := sqlutil.GetTestDBType()
 	if dbType == SQLite {
 		t.Skip()
@@ -96,9 +101,12 @@ func TestMigrationLock(t *testing.T) {
 		sess.Close()
 	})
 
+	key, err := database.GenerateAdvisoryLockId("test")
+	require.NoError(t, err)
+
 	cfg := LockCfg{
 		Session: sess,
-		Key:     "test",
+		Key:     key,
 	}
 
 	t.Run("obtaining lock should succeed", func(t *testing.T) {
@@ -143,7 +151,7 @@ func TestMigrationLock(t *testing.T) {
 		err = dialect.Lock(cfg)
 		require.NoError(t, err)
 
-		err = d2.Lock(LockCfg{Session: sess2})
+		err = d2.Lock(LockCfg{Session: sess2, Key: key})
 		require.Error(t, err)
 		assert.ErrorIs(t, err, ErrLockDB)