actions: runner [container].docker_host variations

* automount
* "" or "-"
* unix:///var/run/docker.sock
* tcp://127.0.0.1:2375

.forgejo/workflows/end-to-end.yml

@@ -77,6 +77,7 @@ jobs:
     steps:
       - uses: https://code.forgejo.org/actions/checkout@v4
       - uses: ./.forgejo/prepare-end-to-end
+      - run: ./end-to-end.sh prepare_dockerd
       - run: su forgejo -c "./end-to-end.sh test_actions"
       - name: full logs
         if: always()