Fix: adagios.rest.view.handle_request, POST case.

request.POST is what must be used. and not request.body.
Use .items() to not get a list of values.

+ simplify and make better the test (json.loads after the assertEqual(status_code, 200).
clean
Fix: need to have 'adagios.okconfig_' in INSTALLED_APPS to have its templates available.
Fix: missed to include 'okconfig_' urls.
More verbose assert.
Don't catch unexpected errors. So we get the stack trace.