Clean up backend codebase

**Is your feature request related to a problem? Please describe.**
I just went through the Backend directory, and I would suggest a thorough clean up.

**Describe the solution you'd like**
- change from commonjs to esmodules
- change some naming conventions
- Bump up some dependencies

**Describe alternatives you've considered**
None

**Additional context**
None.

I would love to get assigned to it.