Refactor GCBM API suggestion

[temitayopelumi]

Description

Hello mentors. In reference to the task given for project two.

I will like to suggest this approach after looking at the FLINT demo last weekend and PR163.

The

1. The upload endpoint stores files in a flat directory structure, rather than nested directories.
2. The upload endpoint accepts a category parameter when uploading files, allowing us to support runs like GCBM.Belize.
3. There is a set_attribute method in the GCBMSimulation class that allows the user set input configuration.

This is still a work in progress. It is not a complete design. But it addresses most of the concerns raised in PR163 and will work well for the current Flint-UI.

I will be glad if I can get the mentor's Feedback on this.

@aornugent @Namyalg @HarshCasper @SanjaySinghRajpoot @Janvi-Thakkar @YashKandalkar

[HarshCasper]

Hi — Thanks a lot for working on this! I would however hold my review on this PR since we wanted to have a plan for the OOP refactor but not actually start with the implementation yet. In case you are selected for Outreachy, we can continue working off this PR (which would need to be rebased with some upcoming new refactors and features). I hope that is fine and I would like to thank you for all the efforts 🙏 🤗

[aornugent]

Hi @temitayopelumi - I think your changes are very aligned with those proposed in #206 and think we should migrate your efforts to the same branch. Thank you for your understanding.