Add testsuite

[strk]

Each API endpoint should have its own test, with fake services started as needed to complete each request.

[strk]

Some tests have been added but it's pretty hard to run them.
Ideally the tests should be runnable right after obtaining the code and running "npm install".
There should be no dependency on any other running module except obvious services like postgresql.

\cc @knutole

[strk]

And ideally outside the docker too, that is (for module-specific testing)