Feature: Support OSCAL group property for processing Rules

[jpower432]

Feature objectives

Update the rules.Memory indexing to support reading and grouping rules by the group Property field.

Caveats / Assumptions

• Related to Rules: Property use of field remarks to should be discontinued in favor of field group compliance-trestle#1873 to remain compatible with trestle outputs

Completion Criteria

• Update test data to use group field instead or remarks for rule groups
• Updates rules.Memory IndexAll method to use group field