Add templates for mariadb, postgres, and valkey

.templates/postgres.yml

@@ -0,0 +1,19 @@
+services:
+  db:
+    container_name: db
+    image: docker.io/library/postgres:17.5
+    restart: unless-stopped
+    environment:
+      - POSTGRES_USER=${POSTGRES_USER}
+      - POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
+      - POSTGRES_DB=${POSTGRES_DB}
+    volumes:
+      - ${APPDATA_PATH}//db:/var/lib/postgresql/data
+    ports:
+      - ${DB_PORT}:5432
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -d ${POSTGRES_DB} -U ${POSTGRES_USER}"]
+      interval: 10s
+      timeout: 5s
+      retries: 3
+      start_period: 10s