* Middleware overhaul!
- Remove unnecessary 'async' keywords from middleware functions
- Ensure all middleware functions we create have names
- Wrap the method contents of all async middleware functions in a try-catch+next(error) pattern
* Use asyncMiddleware wrapper instead of try-catch+next(error) pattern
* Remove unnecessary try-catch+next(error) pattern from context middleware
* remove FEATURE_NEW_VERSIONS from feature-flags.json
* remove process.env.FEATURE_NEW_VERSIONS from include files
* remove process.env.FEATURE_NEW_VERSIONS from lib files
* remove process.env.FEATURE_NEW_VERSIONS from middleware files
* remove process.env.FEATURE_NEW_VERSIONS from script files
* remove process.env.FEATURE_NEW_VERSIONS from test files
* update test fixtures to use new versions as canonical fixtures
