Issue #2195 ADR for waffle flags

[abroddrick]

Ticket

Resolves #2195

Changes

• added adr for waffle flags

Context for reviewers

Setup

Code Review Verification Steps

As the original developer, I have

Satisfied acceptance criteria and met development standards

• [ ] Met the acceptance criteria, or will meet them in a subsequent PR
• [ ] Created/modified automated tests
• [ ] Added at least 2 developers as PR reviewers (only 1 will need to approve)
• [ ] Messaged on Slack or in standup to notify the team that a PR is ready for review
• [ ] Changes to “how we do things” are documented in READMEs and or onboarding guide
• [ ] If any model was updated to modify/add/delete columns, makemigrations was ran and the associated migrations file has been commited.

As a code reviewer, I have

Reviewed, tested, and left feedback about the changes

• [ ] Pulled this branch locally and tested it
• [ ] Reviewed this code and left comments
• [ ] Checked that all code is adequately covered by tests
• [ ] Made it clear which comments need to be addressed before this work is merged
• [ ] If any model was updated to modify/add/delete columns, makemigrations was ran and the associated migrations file has been commited.

Note: Multiple code reviewers can share the checklists above, a second reviewers should not make a duplicate checklist