Build + offer docker image and docker-compose.yml file for easier self-hosting

Tweak login and auth for IP-based setups and setups without email enabled.

docker-compose.dev.yml

@@ -0,0 +1,20 @@
+services:
+  postgresql:
+    image: postgres:15
+    environment:
+      - POSTGRES_USER=postgres
+      - POSTGRES_PASSWORD=fake
+      - POSTGRES_DB=bewcloud
+    restart: on-failure
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    ports:
+      - 5432:5432
+    ulimits:
+      memlock:
+        soft: -1
+        hard: -1
+
+volumes:
+  pgdata:
+    driver: local