docker: rootless image (#10154)

* docker: rootless image

* improve docs + remove check for write perm on custom

* add more info on ssh passtrough

* Add comment for internal ssh server in container config

.drone.yml

@@ -667,6 +667,25 @@ steps:
         exclude:
         - pull_request
 
+  - name: publish-rootless
+    pull: always
+    image: plugins/docker:linux-amd64
+    settings:
+      dockerfile: Dockerfile.rootless
+      auto_tag: true
+      auto_tag_suffix: linux-amd64-rootless
+      repo: gitea/gitea
+      build_args:
+        - GOPROXY=off
+      password:
+        from_secret: docker_password
+      username:
+        from_secret: docker_username
+    when:
+      event:
+        exclude:
+        - pull_request
+
 ---
 kind: pipeline
 name: docker-linux-arm64-dry-run
@@ -745,6 +764,25 @@ steps:
         exclude:
         - pull_request
 
+  - name: publish-rootless
+    pull: always
+    image: plugins/docker:linux-arm64
+    settings:
+      dockerfile: Dockerfile.rootless
+      auto_tag: true
+      auto_tag_suffix: linux-arm64-rootless
+      repo: gitea/gitea
+      build_args:
+        - GOPROXY=off
+      password:
+        from_secret: docker_password
+      username:
+        from_secret: docker_username
+    when:
+      event:
+        exclude:
+        - pull_request
+
 ---
 kind: pipeline
 name: docker-manifest
@@ -766,6 +804,17 @@ steps:
       username:
         from_secret: docker_username
 
+  - name: manifest-rootless
+    pull: always
+    image: plugins/manifest
+    settings:
+      auto_tag: true
+      ignore_missing: true
+      spec: docker/manifest.rootless.tmpl
+      password:
+        from_secret: docker_password
+      username:
+        from_secret: docker_username
 trigger:
   ref:
   - refs/heads/master