Added missing field values in Metaschema modules

[david-waltermire]

Committer Notes

Filled in missing values for a few different Metaschema module fields. These values are required by Metaschema, but cannot be constrained in XML Schema, since they are text values of mixed content.

The absence of these values can cause errors in processing within some tools.

All Submissions:

• Have you selected the correct base branch per Contributing guidance?
• Have you set "Allow edits and access to secrets by maintainers"?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you squashed any non-relevant commits and commit messages? [instructions]
• Do all automated CI/CD checks pass?

By submitting a pull request, you are agreeing to provide this contribution under the CC0 1.0 Universal public domain dedication.

(For reviewers: The wiki has guidance on code review and overall issue review for completeness.)

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you included examples of how to use your new feature(s)?
• Have you updated all OSCAL website and readme documentation affected by the changes you made? Changes to the OSCAL website can be made in the docs/content directory of your branch.

[david-waltermire]

This appears to be failing due to a link check error. Looks like https://github.com/usnistgov/OSCAL/projects/52 is missing.

[iMichaela]

All added field values look good.