Outline typical organization workflows for VPATs for both vendors & clients

Would be useful to know more about both how VPATs are typically generated and how they are consumed.

I assume it is basically like

## Client
- A contracting officer receives the VPAT
- Sends it to both the 508 SME
- Accessibility review done of the VPAT, then returned to the contracting officer with a pass/fail

## Vendor
- Receives a RFP that requires a VPAT
- Either develops a VPAT internally with the accessibility team or contracts out responsibility
- Stores that document for future use by sales
- Contract submitted with the VPAT

Understanding the process better may help to improve it.

No file or test is named. Start with the issue's proposed vendor and client steps, research typical VPAT workflows for both groups, and document the validated process in the appropriate OpenACR documentation; done means both workflows and their handoffs are clearly explained.

Written by the indexing model from the issue text.