Implement running db tests locally

[schuellerf]

This PR implements make db-tests and extends make clean

The tests which are run locally until now used the fsjobqueue and the postgres DB tests were only run in github.

For now this just implements running the tests. More improvements to the tests them selves will be handled in subsequent PRs.

[croissanne]

Personally I think a compose file is a bit overkill. I don't see why we have to run two containers just to run the test, plus it's another container file to maintain for which we need to keep the go version up to date.

In the end running a single container is just a one liner. And I think it's reasonable to expect tern to be installed on the host? After all it's kind of a development dependency here.

[schuellerf]

The idea is, that the setup is as similar to the github actions as possible, so installing a specific postgres version and a specific go version is not a one liner containerfile, I guess.
I'll try to shrink it, although I'm not sure if this easier to keep in sync with the github action.
For the question tern to be on the host, I thought it's more reliable and to avoid possible version hiccups this way.

[croissanne]

The idea is, that the setup is as similar to the github actions as possible, so installing a specific postgres version and a specific go version is not a one liner containerfile, I guess. I'll try to shrink it, although I'm not sure if this easier to keep in sync with the github action. For the question tern to be on the host, I thought it's more reliable and to avoid possible version hiccups this way.

Personally, I think the only way this will be actively maintained is if the github workflow actually calls the make target that you're adding here.

I think the make target should just spin up a postgres container in case it's not running (the exact version doesn't matter imo, as long as it's maintained, we don't depend on a specific version of postgres) and do the test. The workflow should then just call the make target. Similar to what we do for make unit-tests.

[croissanne]

LGTM overall, ig we should edit the comment though?