Simplify Drone config

.drone.yml

@@ -1,28 +1,2 @@
----
+kind: template
-kind: pipeline
+load: docker.yaml
-type: kubernetes
-name: default
-
-steps:
-- name: backend
-  image: plugins/docker
-  settings:
-    repo: harbor.k-space.ee/${DRONE_REPO}
-    registry: harbor.k-space.ee
-    context: backend/
-    dockerfile: backend/Dockerfile
-    username:
-      from_secret: docker_username
-    password:
-      from_secret: docker_password
-- name: frontend
-  image: plugins/docker
-  settings:
-    repo: harbor.k-space.ee/${DRONE_REPO}-frontend
-    registry: harbor.k-space.ee
-    context: frontend/
-    dockerfile: frontend/Dockerfile
-    username:
-      from_secret: docker_username
-    password:
-      from_secret: docker_password