Don't generate redshift findings for default parameter groups

[gebailey]

AWS Redshift generates default parameter groups (e.g. "default.redshift-1.0")
that have certain parameters that can generate findings, such as
"enable_user_activity_logging" == "false", and "require_ssl" == "false".

The user is unable to modify these parameters, so in cases where a default
parameter group exists, findings will be generated which the user has no
ability to remediate.

The "redshift-parameter-group-logging-disabled" and
"redshift-parameter-group-ssl-not-required" rules are modified to only apply to
non-default parameter groups for which the user can be expected to remediate.

Description

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Fixes # (issue)

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• Bug fix (non-breaking change which fixes an issue)
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• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works (optional)
• New and existing unit tests pass locally with my changes

[ramimac]

looks good to me! Thanks

[x4v13r64]

Thanks @gebailey, I've updated the note in the first rule.