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.

frontend/README.md

@@ -0,0 +1,34 @@
+# Mantine Vite template
+
+## Features
+
+This template comes with the following features:
+
+- [PostCSS](https://postcss.org/) with [mantine-postcss-preset](https://mantine.dev/styles/postcss-preset)
+- [TypeScript](https://www.typescriptlang.org/)
+- [Storybook](https://storybook.js.org/)
+- [Vitest](https://vitest.dev/) setup with [React Testing Library](https://testing-library.com/docs/react-testing-library/intro)
+- ESLint setup with [eslint-config-mantine](https://github.com/mantinedev/eslint-config-mantine)
+
+## npm scripts
+
+## Build and dev scripts
+
+- `dev` – start development server
+- `build` – build production version of the app
+- `preview` – locally preview production build
+
+### Testing scripts
+
+- `typecheck` – checks TypeScript types
+- `lint` – runs ESLint
+- `prettier:check` – checks files with Prettier
+- `vitest` – runs vitest tests
+- `vitest:watch` – starts vitest watch
+- `test` – runs `vitest`, `prettier:check`, `lint` and `typecheck` scripts
+
+### Other scripts
+
+- `storybook` – starts storybook dev server
+- `storybook:build` – build production storybook bundle to `storybook-static`
+- `prettier:write` – formats all files with Prettier