Bug 529135 - [Layers] Remove unused plugins and refactor existing code

- removed the dev.ui empty plugin
- removed the update site plugin as this is now handled differently
- renamed folders to stick to a coherent pattern
- moved the tests to the corresponding test plugins (those need to be rewired)
- deactivated broken or un needed (at the time) menus
- created the new layer resource, to be modified

Change-Id: I6fe147495d672dd097bb6d1c0149f3e35144bd13
Signed-off-by: Quentin Le Menez <quentin.lemenez@cea.fr>
175 files changed