Pins Nextcloud to version 27 and switches from Apache to Nginx to improve performance esp. of video streaming (#2)

Streaming videos had been a pain with the default Nextcloud Docker image which uses Apache. This PR will replace that Docker image with Nextcloud 27 FPM and provides an Nginx to serve the app.

Additionally, with moving from the latest Nextcloud (-Apache) image to a pinned version, it will be way clearer, which version is about to be deployed, major upgrades have to be done consciously and without skipping major versions which Nextcloud does not support.

Co-authored-by: Jan Beilicke <dev@jotbe.io>
Reviewed-on: #2

templates/docker-compose.nextcloud.yml.j2

@@ -21,11 +21,8 @@ services:
     restart: unless-stopped
 
   nextcloud-app:
-    image: nextcloud:apache
+    image: nextcloud:27-fpm
     container_name: nextcloud-app
-    networks:
-      - public
-      - default
     depends_on:
       - mysqldb
     volumes:
@@ -33,6 +30,19 @@ services:
       - /etc/localtime:/etc/localtime:ro
     env_file:
       - nextcloud.env
+
+  web:
+    image: nginx
+    restart: always
+    depends_on:
+      - nextcloud-app
+    volumes:
+      - ./nginx.conf:/etc/nginx/nginx.conf:ro
+      - /etc/localtime:/etc/localtime:ro
+      - nextcloud:/var/www/html
+    networks:
+      - public
+      - default
     labels:
       - "traefik.enable=true"
       - "traefik.docker.network=traefik_public"