Huge update for the new migration workflow:

• New name : switch_space_id.
• The given space id is checked in application.properties.
• Most of the treatments have been moved to a "components" folder, allowing us to create easily a new "migrate_several_projects" (or "bulk_project_migration") later.
• The workflow can be launched from the single project view on the nG6 website, when logged a superadmin user.
• The project's space_id is visible to everyone on the single project view.
• A warning indicating that the migration updates the retention has been added to the workflow's form in single project view.
• More logs in ng6.log, and the new log file MoveProject.stdout. (path exemple : [...]/jflow/work/switchspaceid/wf000452/MoveProject_default/MoveProject.stdout)
• CSS updates for the project views.
• For new space_ids, the <space_id>/run and <space_id>/analyze directories will be created if missing.

Issue #129 (closed) Commit db1b75b8