[BACKEND] Neaten endpoint testing and create templates for jest

[jeffplays2005]

Having too many tests in a single file now, would be better to split the tests into individual files(i.e. for each endpoint) and create a template for future use.

Useful links

https://stackoverflow.com/questions/48722930/running-a-global-test-setup-before-each-test-in-jest

BEFORE MERGING

• [ ] Integration test written for services
• [ ] Schemas annotated if adding new models
• [ ] Code generation run (hint: yarn workspace server tsoa spec-and-routes)
• [ ] Appropriate mocks created where possible
• [ ] PR Reviewed (For non-trivial changes)
• [ ] Changes tested after rebasing on master or merging in master (hint: git fetch origin master:master, then git rebase master or git merge master)
• [ ] All required PR checks passing