refactor(frontend api interactions)

* Complete redesign of the api actions / reducers,
* Now makes use of Axios,
* No more black magic,
* Doc updated,

BREAKING: All `...Specific` reducers results are no under `...One` and `readSpecific` moved to `readOne`

Also,
* Fixed bug regarding opposite user_can_moderate value returned by backend

Fixes #98
6 jobs for !83 with refactor/redux_REST in 4 minutes and 28 seconds (queued for 1 second)
detached
Status Job ID Name Coverage
  Check
passed #490681
docker
check_back

00:00:21

passed #490682
docker
check_front

00:01:31

 
  Test
passed #490683
docker
test_back

00:00:44

90.0%
passed #490684
docker
test_frontend

00:00:46

 
  Lint
passed #490686
docker
eslint

00:00:51

passed #490685
docker
flake8

00:00:13