Add ADR for attachment handling for #1061

[aj-stein-gsa]

Committer Notes

Closes #1061.

All Submissions:

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• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
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• If applicable, have all FedRAMP Documents Related to OSCAL Adoption affected by the changes in this issue have been updated.?
• If applicable, does this PR reference the issue it addresses and explain how it addresses the issue?

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[aj-stein-gsa]

This is not necessarily ready for review right right now, but it will be later in the afternoon and more importantly for others first thing Monday once I am on leave. So on that note, I will be changing status for my future aspirations now. 😄

[wandmagic]

rmf-use is a good choice for the param, i like this solution