refactor: no more need for initial admin email env var

docker-compose.yml

@@ -36,7 +36,6 @@ services:
       - FILE_STORAGE=/app/storage
       - DATABASE_URL=postgresql://${POSTGRES_USER:-thingport}:${POSTGRES_PASSWORD:-thingport}@db:5432/${POSTGRES_DB:-thingport}?schema=public
       - CORS_ORIGINS=${CORS_ORIGINS:-}
-      - INITIAL_ADMIN_EMAIL=${INITIAL_ADMIN_EMAIL:-}
       - AUTH_SECRET=${AUTH_SECRET:-changeme-secret}
       - AUTH_TOKEN_TTL=${AUTH_TOKEN_TTL:-43200}
       - PUBLIC_URL=${PUBLIC_URL:-}