GTNPORTAL-3450: Impossible to upload file in Content Explorer when tmpdir does not exist

Fix description:
- When uploading a file, check if tmpdir exists. If not, create it
GTNPORTAL-3486 Redirect to /sso instead of /login when SSO is enabled
GTNPORTAL-3486 Redirect to /sso instead of /login when SSO is enabled
GTNPORTAL-3508: Imported applications are public by default

Fix description:
* When adding an application into a category, the access permission to this application is restricted to administrators group.
* The same default permission is applied to categories and applications imported in batch by clicking "Import Applications".