Cfripper

Improvements
- Add EKS permissions that accept wildcard resource only

Improvements
- Add `stack_id` to log output when failing to convert a YML template to JSON.
- Various minor test improvements
- Added CLI args for aws account id and aws principals
- Fix an issue in `S3BucketPublicReadAclAndListStatementRule` where it could crash if the model was unresolved
- Center logo (thanks lpmi-13)
- Run tests in python 3.9

Improvements
- Downgrade logging severity from exception to warning when there is no stack in AWS

Improvements
- Handle AWS throttling errors when listing exports for a given account and region
- If we get a throttling error, we actually sleep for some time before retrying (before we were sleeping for 0 seconds)

Improvements
- Decrease logging level when loading external filters
- Decrease logging level on known AWS errors such as AccessDenied when listing exports and
throttling errors on getting a template from AWS CloudFormation.

Breaking changes
- `Filter` include the set of rules in which it is applied.
- `RuleConfig` only contains `rule_mode` and `risk_value` now.
- Removes old whitelisting methods in favour of Filters
- Rename `RuleMode.WHITELISTED` to `RuleMode.ALLOWED`, and all `whitelist` word in strings.
- Add debug flag to `Filter` class.
Improvements
- Implements `pluggy` https://github.com/pytest-dev/pluggy to enable dynamic rule loading.
- Add support to load filters from external files