refactor: simplify Cloud Code tests and FunctionsRouter

[dblythy]

New Pull Request Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am creating this PR in reference to an issue.

Issue Description

Works towards making core code and spec more readable.

Related issue: #7563

Approach

Refactors existing code to better standards.

TODOs before merging

• [x] Add test cases
• [x] Add entry to changelog

[parse-github-assistant[bot]]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[mtrezza]

Woooo, what an undertaking! Refactoring is something that often stays behind unfortunately. Great that you pick this up!

[dblythy]

I'm happy to continue working through, just wanted to see your thoughts 😊

[codecov[bot]]

Codecov Report

Merging #7564 (7402aad) into master (68a3a87) will decrease coverage by 9.15%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #7564      +/-   ##
==========================================
- Coverage   93.95%   84.80%   -9.16%     
==========================================
  Files         181      181              
  Lines       13328    13318      -10     
==========================================
- Hits        12522    11294    -1228     
- Misses        806     2024    +1218     

Impacted Files	Coverage Δ
src/Routers/FunctionsRouter.js	100.00% <100.00%> (+5.88%)	:arrow_up:
...dapters/Storage/Postgres/PostgresStorageAdapter.js	2.47% <0.00%> (-92.90%)	:arrow_down:
src/Adapters/Storage/Postgres/PostgresClient.js	5.00% <0.00%> (-65.00%)	:arrow_down:
src/Controllers/UserController.js	95.34% <0.00%> (-2.33%)	:arrow_down:
src/Controllers/FilesController.js	92.00% <0.00%> (-2.00%)	:arrow_down:
src/Controllers/index.js	96.66% <0.00%> (-1.12%)	:arrow_down:
src/Routers/UsersRouter.js	93.82% <0.00%> (-0.57%)	:arrow_down:
src/middlewares.js	96.92% <0.00%> (-0.44%)	:arrow_down:
src/RestWrite.js	93.73% <0.00%> (-0.32%)	:arrow_down:
src/Controllers/SchemaController.js	97.16% <0.00%> (-0.19%)	:arrow_down:
... and 3 more

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[mtrezza]

Could you please resolve the conflict?