Draft: chg: test: Add stress tests with DoH and DoT

Validation pipeline: https://gitlab.isc.org/isc-projects/bind9/-/pipelines/160984

Prerequisites:

• isc-private/devops!11
• bind9-qa!9

Things to consider:

• FreeBSD DoH jobs are not added because Flamethrower queries always timeout.
• This adds 15 more CI jobs:
  • Linux (AWS autoscaler): (auth + recursive + RPZ) * (DoH + DoT) * (amd64 + arm64) = 12
  • FreeBSD (one FreeBSD runner): (auth + recursive + RPZ) * (DoT) * (amd64) = 3
• Autoscaler is not yet present on FreeBSD. Adding 3 CI jobs (i.e., DoT) run serially adds 3 hours to the pipeline runtime. Should we add just one FreeBSD DoT job to limit the runtime?
• DoH/DoT performance is slightly lower than pure TCP, so the threshold for the test to pass must be lowered by 5-10% (see isc-private/bind-qa!40).