add testdata to docker setup. use sqlite in 'dev' scenario and mailpit in 'testing'

deploy/dev/docker-compose.yml

@@ -3,20 +3,15 @@ services:
     build:
       context: ../../core
       dockerfile: ../deploy/dev/Dockerfile.backend
-    command: bash -c 'python manage.py migrate && python manage.py runserver 0.0.0.0:8000'
+    command: bash -c 'python manage.py migrate && python testdata.py && python manage.py runserver 0.0.0.0:8000'
     environment:
       - HTTP_HOST=core
-      - DB_HOST=db
-      - DB_PORT=3306
-      - DB_NAME=system3
-      - DB_USER=system3
-      - DB_PASSWORD=system3
+      - DB_FILE=dev.db
     volumes:
       - ../../core:/code
+      - ../testdata.py:/code/testdata.py
     ports:
       - "8000:8000"
-    depends_on:
-      - db
 
   frontend:
     build:
@@ -31,18 +26,3 @@ services:
       - "8080:8080"
     depends_on:
       - core
-
-  db:
-    image: mariadb
-    environment:
-      MARIADB_RANDOM_ROOT_PASSWORD: true
-      MARIADB_DATABASE: system3
-      MARIADB_USER: system3
-      MARIADB_PASSWORD: system3
-    volumes:
-      - mariadb_data:/var/lib/mysql
-    ports:
-      - "3306:3306"
-
-volumes:
-  mariadb_data: