feat: Initialize SQLAlchemy backend and database structure

- Added SQLAlchemy initialization script for backend setup.
- Created SQLAlchemy prompts for generating database models with LLMs.
- Introduced Docker Compose configuration for PostgreSQL service.
- Added SQL script to enable necessary PostgreSQL extensions.

__marimo__/session/prompts_plantillas.py.json

@@ -0,0 +1,27 @@
+{
+  "version": "1",
+  "metadata": {
+    "marimo_version": "0.14.17"
+  },
+  "cells": [
+    {
+      "id": "Hbol",
+      "code_hash": "1d0db38904205bec4d6f6f6a1f6cec3e",
+      "outputs": [
+        {
+          "type": "data",
+          "data": {
+            "text/plain": ""
+          }
+        }
+      ],
+      "console": []
+    },
+    {
+      "id": "LPNa",
+      "code_hash": null,
+      "outputs": [],
+      "console": []
+    }
+  ]
+}