Refactored database management into multiple files

Description

Refactored the database management module. The module still functions identically, it's just a lot nicer to look at.

Changes Made

• Change 1: Separated database management functions in to separate files, plus an init file. Benefits:
  • Improved readability
  • Separation of private and public functions
• Change 2: Refactored some of the larger functions by breaking them down into their component parts. Bemefits:
  • Reduced complexity
  • Improved readability
  • Improved documentation
• Change 3: Made a few minor changes to test_database_management
  • Restructured imports, since private functions can no longer be imported directly
  • Fixed a small issue with an out-of-range value.

Test Plan

make test

Checklist

• Code follows the project's coding style and conventions.
• Automated tests for the changes have been added or existing tests have been updated.
• Code coverage for new or modified code is maintained or improved.
• The code builds and runs without errors or warnings.
• Documentation has been updated to reflect the changes made.
• All discussions and feedback on the PR have been addressed.
• CI/CD pipelines pass successfully, including any required checks or tests.
• The PR has been reviewed and approved by the designated reviewers.

Additional Notes

• Please prioritize your own work - as long as nobody makes changes to the database_management module, this merge can be performed at pretty much any time.
• I discovered most of these complexity issues with the radon package - check it out, it's pretty cool!