docs: Improve MinIO section in the readme file

[xmnlab]

Improve MinIO section in the readme file: https://github.com/thegraphnetwork/EpiGraphHub/blob/main/README.md#minio

it should have:

• how to access the UI
• how to create a bucket
• how to upload files using pandas
• how to access files using pandas

[xmnlab]

@YurelyCamacho could you work on this task?

[YurelyCamacho]

Hola @xmnlab no conozco esto ¿Dónde puedo guiarme?
Comenzaría con esto luego de avanzar en la documentación acá https://github.com/thegraphnetwork/epigraphhub-lib-docs

[xmnlab]

this is the official documentation:
https://min.io/docs/minio/kubernetes/upstream/