feat: add rules-to-control mappings to support implementation/requirement specific settings

[jpower432]

Description

Creates logic around reading OSCAL Control Implementation sets and the application of implementation or requirement specific options to RuleSets.

Partially closes #13

Reviewer Hints

• Suggest to review by commit. Details for each change are in the commit message.
• The main commit with the feature is the final commit. The first three are smaller refinements. They can go on their own PR, if desired.

Types of changes

• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
  Small updates to the rules.Store interface. However, this codebase has not had an initial release yet.

Quality assurance (all should be covered).

• 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
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes
• All commits are signed-off.