Refactor the structure of the whole library

[lokeshmohanty]

• move src/scirex to scirex
• move all current modules into experimental
• update the repository outline as per https://github.com/airexlab/ScientificML/issues/2
• update the generated docs
• fix github actions
• fix copyright issues
• move a module from experimental to stable to confirm everything works properly (transformers)
• fix all formatting issues
• ensure all code quality check work perfectly

[lokeshmohanty]

Updated the repository outline as per https://github.com/airexlab/ScientificML/issues/2

[lokeshmohanty]

@protyush-airex-lab @harshdeep-zenteiq-ai I have updated the structure without losing any information. I have added the transformers module with a very simple implementation. We can iteratively increase the complexity of all the modules. I have confirmed the code quality checker, test runner and documentation generator are working properly and in sync with github actions.

I am done with the re-structuring in this pull request. Further changes(except issues) can done in another pr.

Meanwhile, I will keep adding the other modules in a separate branch and pr.

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