Draft: dev: Run functional tests on testing as well as unstable

• virtualbox-amd64-dev builder is replaced with virtualbox-amd64-testing-dev and virtualbox-amd64-unstable-dev.

• app-server-dev builder is replaced with app-server-testing-dev and app-server-unstable-dev.

Not tested: I could not verify if it is correct. (Maybe a script to spin up buildbot would help here.)

Signed-off-by: James Valleroy jvalleroy@mailbox.org