Add CI testing for clojure.

[crkrenn]

@patcon, @metasoarous, @ballPointPenguin,

There already is a directory of tests for math. Can these be integrated into the CI/e2e testing?

I'm asking now, because I'd like to make sure that bumping java from 1.7 to 1.8 won't break anything.

Thanks!

-Chris

To Do

^{Added by patcon :pray:}

• [x] upgrade java from 1.7 to 1.8 https://github.com/pol-is/polis/pull/506
• [x] run unit tests https://github.com/pol-is/polis/pull/506
• [ ] run integration tests
• [ ] add readme badges for build status
• [ ] remove junk line from workflow https://github.com/pol-is/polis/pull/506/files#r465461528

[patcon]

Yeah, it'd be great to get those running! Hadn't noticed those :)

[patcon]

@metasoarous Is there enough of a cross-cut of testing that you'd feel safe upgrading packages/java once we got this running? re: https://github.com/pol-is/polis/issues/400

[patcon]

I'm asking now, because I'd like to make sure that bumping java from 1.7 to 1.8 won't break anything.

Related: https://github.com/pol-is/polis/issues/400#issuecomment-668395487