Add OpenAI and PostgreSQL credential management

- Implemented OpenAICredencial class for managing OpenAI API keys.
- Created OpenAICredencialModel and OpenAICredencialMapper for SQLAlchemy integration.
- Developed OpenAICredencialRepo for CRUD operations on OpenAI credentials.
- Established OpenAICliente class for interacting with OpenAI API.
- Introduced PostgresCredencial class for managing PostgreSQL connection details.
- Created PostgresCredencialModel and PostgresCredencialMapper for SQLAlchemy integration.
- Developed PostgresCredencialRepo for CRUD operations on PostgreSQL credentials.
- Added base connection class and PostgreSQL connection implementation.
- Included environment variable loading for sensitive data management.

Credenciales.ipynb

@@ -2,13 +2,13 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "id": "5206b9c6",
    "metadata": {},
    "outputs": [],
    "source": [
-    "from backend.ConexionSql.Postgres_conexion import PostgresConexion\n",
-    "from backend.Credenciales.postgres_credencial_mmr import PostgresCredencialRepo\n",
+    "from src.ConexionSql.Postgres_conexion import PostgresConexion\n",
+    "from src.Credenciales.postgres_credencial_mmr import PostgresCredencialRepo\n",
     "\n"
    ]
   },