Add basic backend infrastructure

Signed-off-by: Felipe Cardoso <felipe.cardoso@hotmail.it>

backend/requirements.txt

@@ -0,0 +1,13 @@
+fastapi>=0.104.0
+uvicorn>=0.24.0
+python-multipart>=0.0.6
+python-jose[cryptography]>=3.3.0
+passlib[bcrypt]>=1.7.4
+pydantic>=2.4.2
+pydantic-settings>=2.0.3
+paramiko>=3.3.1
+python-dotenv>=1.0.0
+aiofiles>=23.2.1
+pytest>=7.4.3
+httpx>=0.25.1
+pytest-asyncio>=0.21.1