Add SQL execution on log and indexes on table repository and comment (#7740)

* add index on comment

* add SQL execution time on log and index owner_id on repository

* add migration

models/repo.go

@@ -129,7 +129,7 @@ func NewRepoContext() {
 // Repository represents a git repository.
 type Repository struct {
 	ID            int64  `xorm:"pk autoincr"`
-	OwnerID       int64  `xorm:"UNIQUE(s)"`
+	OwnerID       int64  `xorm:"UNIQUE(s) index"`
 	OwnerName     string `xorm:"-"`
 	Owner         *User  `xorm:"-"`
 	LowerName     string `xorm:"UNIQUE(s) INDEX NOT NULL"`