Package testing

[wavexx]

We should ensure basic functionality works without relying too much on user testing.
For example, with the REST interface there's a lot we can already test automatically.

• Basic DB setup on the 3 different backends we support
• DB upgrade across releases using all backends
• Ticket creation / download / expiry via dl-cli
• Grant creation via dl-cli

We could even ensure no php warnings are generated by checking the log file after all tests are run.