React 17 in `dev`

[miles-grant-ibigroup]

Blocked pending e2e test dockerization

Checklist

• [x] Appropriate branch selected (all PRs must first be merged to dev before they can be merged to master)
• [x] Any modified or new methods or classes have helpful JSDoc and code is thoroughly commented
• [x] The description lists all applicable issues this PR seeks to resolve
• [x] The description lists any configuration setting(s) that differ from the default settings
• [x] All tests and CI builds passing
• [ ] The description lists all relevant PRs included in this release (remove this if not merging to master)
• [ ] e2e tests are all passing (remove this if not merging to master)

Description

This has been merged into dev-flex, now it's dev's turn