[REF] refactor CI workflows (#878)

* refactor validation ci

* rename workflow

* set up base workflow

* try moving MAC toolbox

* add octave and matlab setup

* add moxunit set up

* add matlab test job

* try single workflow for all tests

* try different if syntax

* try adding system tests

* cancel previous jobs

* typo

* display script name

* try with dummy value

* try again

* try again

* remove script from matrix

* reuse script

* revert

* try another matrix

* try again

* rm previous workflows

Author: Remi-Gau