Enable feature flag in 4.4 backport and other housekeeping

The pre-release checklist:
1. Enable feature flag by default
2. Make sure all integration tests are actually running and passing
3. All intensities should be off by default, make sure tests are enabling them back. However, let all the tests to run for some time before doing that
4. Revisit and close all backport tickets, cut the release
5. Write readme doc
6. Scan the code for TODOs