Feat/api skills

Issue #648 Implement skills api We need a skills api endpoint so that the data cleaning process has access to all the skills in the platform, instead of just user skills (which is what has been implemented for the moment).

/api/skills

returns a json array of objects each containing

skill id skill name clean skill name (if available)

_Draft of API skills. _

Add skills_controller file into app/controller/API

Routes create

Add spec file / Need do write test.