Add Abbreviation to OSCAL

[mruge]

User Story:

When creating tools, graphics, or supplementary material related to OSCAL it is often convenient to use a short name or abbreviation for the Model.

Goals:

Add a recommended or common abbreviation to the metaschema. Most of these are already used, just not specifically stated in a property within the metaschema.

Recommended Short Names

Catalog - CTLG Profile - PRFL Component Definition - CDEF SSP - SSP Assessment Report - AR Assessment Plan - AP Poam - POAM

Dependencies:

N/A

Acceptance Criteria

• [ ] All OSCAL website and readme documentation affected by the changes in this issue have been updated. Changes to the OSCAL website can be made in the docs/content directory of your branch.
• [ ] A Pull Request (PR) is submitted that fully addresses the goals of this User Story. This issue is referenced in the PR.
• [ ] The CI-CD build process runs without any reported errors on the PR. This can be confirmed by reviewing that all checks have passed in the PR.

{The items above are general acceptance criteria for all User Stories. Please describe anything else that must be completed for this issue to be considered resolved.}

[david-waltermire]

This will require changes to the Metaschema syntax. Created usnistgov/metaschema#185 for this.