This allows tracking rather than throttling certain or all configured
throttles.

This can be done by setting the GITLAB_THROTTLE_DRY_RUN env variable
to a comma separated list of throttles. Each of the throttles
specified in that list will be tracked instead of throttled.

To disable throttling for all configured throttles, we can specify '*'
in the environment variable.

When a request would be rate-limited but dry-run mode is set, the
request continues as normal, but we emit a log message.