* Use local copies of pebble certs as docker image contains outdated versions
* Update the preferred chain used in Staging
* Put test API keys in github secrets, add code to create/delete test domains to prevent misuse
* Simplify dns_add_acmedns

For now, srvrco is excluded.

The domain name will be <repo>-<os>-getssl.<duckdns.org|freedns.org>

Must be added to accounts on these services.

Note: To add the secrets to your repository on GitHub

Goto Actions -> Settings -> Secrets

New Repository Secret

Add DUCKDNS_TOKEN
Add DYNU_API_KEY

The test harness will suppress output unless an error occurs.

Upgrade testing was failing in forked repos CI because the
source repo was hard-coded.  Use the CI environment to use
the fork's repo.