chore(db): introduce db.Session and db.EngineMigration interfaces (#37746)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: wxiaoguang <2114189+wxiaoguang@users.noreply.github.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/migrations/v1_7/v73.go

@@ -3,11 +3,9 @@
 
 package v1_7
 
-import (
-	"xorm.io/xorm"
-)
+import "code.gitea.io/gitea/models/db"
 
-func AddMustChangePassword(x *xorm.Engine) error {
+func AddMustChangePassword(x db.EngineMigration) error {
 	// User see models/user.go
 	type User struct {
 		ID                 int64 `xorm:"pk autoincr"`

models/migrations/v1_7/v74.go

@@ -3,9 +3,9 @@
 
 package v1_7
 
-import "xorm.io/xorm"
+import "code.gitea.io/gitea/models/db"
 
-func AddApprovalWhitelistsToProtectedBranches(x *xorm.Engine) error {
+func AddApprovalWhitelistsToProtectedBranches(x db.EngineMigration) error {
 	type ProtectedBranch struct {
 		ApprovalsWhitelistUserIDs []int64 `xorm:"JSON TEXT"`
 		ApprovalsWhitelistTeamIDs []int64 `xorm:"JSON TEXT"`

models/migrations/v1_7/v75.go

@@ -4,11 +4,12 @@
 package v1_7
 
 import (
+	"code.gitea.io/gitea/models/db"
+
 	"xorm.io/builder"
-	"xorm.io/xorm"
 )
 
-func ClearNonusedData(x *xorm.Engine) error {
+func ClearNonusedData(x db.EngineMigration) error {
 	condDelete := func(colName string) builder.Cond {
 		return builder.NotIn(colName, builder.Select("id").From("`user`"))
 	}