Install and run the generator on CI

[sondr3]

This was something that I wanted to do for the last version, but I couldn’t do it. Often I’d do a minor change in the generator that the tests do not catch, for example spelling errors in a config file or misconfiguration. It would be nice to be able to actually install the generator on CI, run the commands we want to test and verify the output. Would make testing a lot more robust instead of just checking that the files exists and the templates were filled in.