Whitenoise

Closes #63. 

See merge request !19

* using gevnts for async requests handling of gunicorn
* serving the static frontend via gunicorn
* split requirements into dev and general
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Refactor views to viewsets

Closes #58.

See merge request !17

* IT waS A FUCKIng tyPO
* ran isort and flake8 and fixed reported issues

Merge branch 'refactor-views-to-viewsets' of gitlab.gwdg.de:j.michal/grady into refactor-views-to-viewsets

Currently students and tutors have access to the /tutor/ endpoint in the browsable api and at least get a 200 response in the tests for the /student/ endpoint however can not access this one in the browsable api.

* no url configuration needed simply register viewset with router
* now using DefaultRouter, meaning api root is now browsable
* merged some views
* makes it easier to include api schema later
* Ran isort and updated docstring

Backend tests

Closes #50

See merge request !16

* Also added docstrings to classes and module in views.py
* Removed a logging statement from StudentApiView

- changed unittester from ./manage.py test to pytest in CI
- implemented tests for various views see previous commits
- coverage should now produce html output for test coverage

* ran isort on all test files

allowed to fail

* also moved test concerning access rights to another test suite

This reverts commit 0acfd677.

The methods in core.tests.data_factories.py are not finished nor good and overlap with GradyUserFactory.