What was added?

Added .flake8, poetry.lock, pyproject.toml, and .markdownlint.json to define coding standards that we will require and use when building future solutions
Contributors should use the standards defined within these files before submitting pull requests
Existing solutions will get refactored to these standards in future updates
Added S3 BucketKeyEnabled to the solutions that create S3 objects (e.g. CloudTrail, GuardDuty, and Macie)

What was changed?

Modified the directory structure to support multiple internal packages (e.g. 1 for each solution)
The folder structure also allows for tests (integration, unit, etc.). See Real Python Application with Internal Packages.
Renamed folders and files with snake_case to align with PEP8 Package and Module Names
Modified links within README.md files to align with the updated folders and file names
Updated the README.md files to provide consistency and improved formatting
Renamed parameter and template files to sra-<solution_name>...
Updated default values for parameters for resource names with sra- prefix to help with protecting resources deployed

Removed the AWS Config Aggregator account solution since AWS Control Tower deploys an account aggregator within the Audit account

@tekdj7 made his first contribution with #66, which will make a big impact on the overall code consistency and quality