[Update Roadmap] Backend Developer Roadmap

### Description

Update and and more content in Backend Developer Roadmap directory

### Screenshots

_No response_

### Additional information

keep the format as per the [Web3-Developer](https://github.com/BuildersChain/Developers-Roadmap/tree/main/WEB3-Developer) roadmap directory and before creating new roadmap send a PR of screenshot of how your roadmap will look like