Prepare transition to Gitea, set up Drone CI

.drone.yml

@@ -0,0 +1,18 @@
+---
+kind: pipeline
+type: docker
+name: check
+
+steps:
+  - name: yamllint
+    image: python:3.9-alpine
+    commands:
+      - pip install yamllint==1.25.0
+      - yamllint -c .yamllint.yml .
+
+  - name: ansible-lint
+    image: python:3.9-alpine
+    commands:
+    - pip install ansible-lint==4.3.7
+    - ansible-lint *.yml
+...