Adding listing, viewing and downloading of recordings

[banpei-dbart]

Adding listing, viewing and downloading of recordings as described in GROW-1083

[Ali-BenZarrouk-MB]

There are no unit tests. Consider adding the needed ones python-rest-api/tests/. And as an extra optional point if you feel like, fail the build if unit test coverage is less than the latest green build :).

[banpei-dbart]

There are no unit tests. Consider adding the needed ones python-rest-api/tests/. And as an extra optional point if you feel like, fail the build if unit test coverage is less than the latest green build :).

I have added unit tests for most of my code (download can't be tested as it's difficult to mock) and tried to add code coverage. I did manage to change the unit tests to pytest and include coverage, but this lead to a dependency issue with pypy3.5, so that's on ignore for now.

For coverage checks: I tried to also pass the coverage to coveralls, but this hasn't been set up for this repo. Any ideas how to proceed with this?