Enable/disable owner and repo projects independently (#28805)

Part of #23318 

Add menu in repo settings to allow for repo admin to decide not just if
projects are enabled or disabled per repo, but also which kind of
projects (repo-level/owner-level) are enabled. If repo projects
disabled, don't show the projects tab.


![grafik](https://github.com/go-gitea/gitea/assets/47871822/b9b43fb4-824b-47f9-b8e2-12004313647c)

---------

Co-authored-by: delvh <dev.lh@web.de>

routers/web/repo/setting/setting.go

@@ -533,6 +533,9 @@ func SettingsPost(ctx *context.Context) {
 			units = append(units, repo_model.RepoUnit{
 				RepoID: repo.ID,
 				Type:   unit_model.TypeProjects,
+				Config: &repo_model.ProjectsConfig{
+					ProjectsMode: repo_model.ProjectsMode(form.ProjectsMode),
+				},
 			})
 		} else if !unit_model.TypeProjects.UnitGlobalDisabled() {
 			deleteUnitTypes = append(deleteUnitTypes, unit_model.TypeProjects)