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
9 jobs for master in 4 minutes and 18 seconds (queued for 1 second)
Status Job ID Name Coverage
  Check
passed #490687
docker
check_back

00:00:20

passed #490688
docker
check_front

00:00:58

 
  Test
passed #490689
docker
test_back

00:00:44

90.0%
passed #490690
docker
test_frontend

00:00:46

 
  Lint
passed #490692
docker
eslint

00:00:49

passed #490691
docker
flake8

00:00:12

 
  Svg Gen Docu
passed #490693
docker
generate_UML_svg

00:00:14

 
  Documentation
passed #490694
docker
pages

00:00:11

 
  Deploy
passed pages:deploy

00:00:00