Support actions and reusable workflows from private repos (#32562)

Resolve https://gitea.com/gitea/act_runner/issues/102

This PR allows administrators of a private repository to specify some
collaborative owners. The repositories of collaborative owners will be
allowed to access this repository's actions and workflows.

Settings for private repos:


![image](https://github.com/user-attachments/assets/e591c877-f94d-48fb-82f3-3b051f21557e)

---

This PR also moves "Enable Actions" setting to `Actions > General` page

<img width="960" alt="image"
src="https://github.com/user-attachments/assets/49337ec2-afb1-4a67-8516-5c9ef0ce05d4"
/>

<img width="960" alt="image"
src="https://github.com/user-attachments/assets/f58ee6d5-17f9-4180-8760-a78e859f1c37"
/>

---------

Signed-off-by: Zettat123 <zettat123@gmail.com>
Co-authored-by: ChristopherHX <christopher.homberger@web.de>

routers/web/user/search.go

@@ -16,10 +16,14 @@ import (
 
 // SearchCandidates searches candidate users for dropdown list
 func SearchCandidates(ctx *context.Context) {
+	searchUserTypes := []user_model.UserType{user_model.UserTypeIndividual}
+	if ctx.FormBool("orgs") {
+		searchUserTypes = append(searchUserTypes, user_model.UserTypeOrganization)
+	}
 	users, _, err := user_model.SearchUsers(ctx, user_model.SearchUserOptions{
 		Actor:       ctx.Doer,
 		Keyword:     ctx.FormTrim("q"),
-		Type:        user_model.UserTypeIndividual,
+		Types:       searchUserTypes,
 		IsActive:    optional.Some(true),
 		ListOptions: db.ListOptions{PageSize: setting.UI.MembersPagingNum},
 	})