Added a script to cleanup recordings. While doing this, moved the CI
matrix generation to a separate script so there is a single source of
truth for the matrix.
Ran the cleanup script as:
```
PYTHONPATH=. python scripts/cleanup_recordings.py
```
Also added this as part of the pre-commit workflow to ensure that the
recordings are always up to date and that no stale recordings are left
in the repo.
Wanted to re-enable Responses CI but it seems to hang for some reason
due to some interactions with conversations_store or responses_store.
## Test Plan
```
# library client
./scripts/integration-tests.sh --stack-config ci-tests --suite responses
# server
./scripts/integration-tests.sh --stack-config server:ci-tests --suite responses
```
