Refactor unstructured codebase and integrate linting checks

Since the judege-taskmaster and ** judge-api** codebases are used in production applications, the code needs to follow particular standards and guidelines, which can greatly increase its maintainability as a community project.

Therefore linters should be set as would be done under https://github.com/coding-blocks/judge-taskmaster/issues/41 up to force standard code guidelines on the repository.

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Working on it, would send PR as soon as the issue acknowledged.