Add DNS Shotgun performance tests to nightly pipelines
This is basically an additional coverage of the resolver functionality, focusing on testing the behavior of various transport protocols under load. The tests provide a comparison of response latency, memory consumption and CPU utilization to a previously released version - plotted with different charts. The output of the test is a link to such a result page which needs to be examined manually (similar to perflab).
Ideally, the performance tests would be longer than 5 minutes, but our current benchmarking automation needs additional tweaks before the runtime can be significantly increased. DoH should also be added in the future. I skipped that for now, as it also requires more tweaking and investigation and I didn't want to increase the scope of this effort further.
The new jobs should be considered informational as they require manual inspection of charts - mostly something QA will take a look at when getting closer to release. The jobs aren't executed in regular MR pipelines.
Example pipeline: https://gitlab.isc.org/isc-projects/bind9/-/pipelines/150082