Improved docstrings

Description

Improved / standardized all existing docstrings.

Sorry in advance, these changes might take a bit to read through.

Changes Made

• Change 1: Re-wrote docstrings in database_management.py
• Change 2: Re-wrote docstrings in provider.py
• Change 3: Re-wrote docstrings in schemas.py
• Change 4: Re-wrote docstrings in user_io.py

Test Plan

• No executable code was changed (except for one minor fstring bug in an error message)

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.