Nuxeo IDE project creation (archetype) system so also manage to load from a folder

Is already be able to load archetypes from zip files. In some case we want it to be able to load from a not zip file: in nuxeo ide webengine plugins, we don't want to store the archetype file as zip file in the scm as we won't see modifications made and it would make harder any modification.

This task consist of

• Update the code to handle folders (and keep zip files)
• Unzip the archetypes in nuxeo-ide-webengine plugin and removed the zip files.