Add user_energy function back, separate unit tests, cache data_request flag before main loop

[wheeendiii]

Description

• Add user_energy function back in process.py after MySQL upgrade to 8. x.
• Separate unit tests for all aggregation functions.
• Cache data_request flag before the main loop.

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] Testing
• [ ] Change that requires a documentation update

How Has This Been Tested?

Run all unit test files to check output CSV to the current folder. Run unit test files and check the result of unit tests (should say "ok").

• [x] Manual Test
• [x] Unit Test
• [ ] Integration / End-to-End Test

Test Configuration:

• Python version 3.8.11
• Mysql 8

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas that are not self-documenting
• [ ] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] My changes have no unnecessary logging
• [ ] I have added tests that prove my fix is effective or that my feature works, for sufficiently complex features
• [x] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules
• [x] Sensitive info like tokens, secrets, and passwords have been removed before submitting

Modified from this article: Phillip Johnston, “A GitHub Pull Request Template for Your Projects - Embedded Artistry,” Embedded Artistry, Aug. 04, 2017. https://embeddedartistry.com/blog/2017/08/04/a-github-pull-request-template-for-your-projects/ (accessed Jul. 22, 2021).