ENYO-3066: add a textarea to deal with project description

Related JIRA: https://enyojs.atlassian.net/browse/ENYO-3066

Add a textarea in the project tab of the project properties popup to deal with project description.
It is placed between project's settings and available services (so after bootplates selection).
It is available at the creation/edition/duplication of a project.
NB: Modifying project.json directly does not modify project properties

Enyo-DCO-1.1-Signed-off-by: Vincent HERILIER vincent.herilier@hp.com