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>

templates/swagger/v1_json.tmpl

@@ -19570,6 +19570,11 @@
           "type": "boolean",
           "x-go-name": "Private"
         },
+        "projects_mode": {
+          "description": "`repo` to only allow repo-level projects, `owner` to only allow owner projects, `all` to allow both.",
+          "type": "string",
+          "x-go-name": "ProjectsMode"
+        },
         "template": {
           "description": "either `true` to make this repository a template or `false` to make it a normal repository",
           "type": "boolean",
@@ -22491,6 +22496,10 @@
           "type": "boolean",
           "x-go-name": "Private"
         },
+        "projects_mode": {
+          "type": "string",
+          "x-go-name": "ProjectsMode"
+        },
         "release_counter": {
           "type": "integer",
           "format": "int64",