CLI command import imports properties that should not be imported

[jajm]

Describe the bug
When importing a JSON file using the Web interface, some properties are automatically excluded. For instance for dashboards, the following properties are never imported:

• dashboard.author;
• dashboard.createdBy;
• dashboard.createdOn;
• dashboard.isPublic;
• dashboard.isShared;
• dashboard.owner;
• dashboard.parentFolder;

The CLI command import doesn't do that. This may result in dashboards/reports that references users (or shared space folder) that do not exist

To Reproduce
Steps to reproduce the behavior:

1. Create a user 'user1', give it the permission to create dashboards
2. Log in as user1 and create a dashboard
3. Log in as admin and export the dashboard
4. Remove user1 and its dashboard
5. Import the dashboard using the CLI
6. See that the imported dashboard appear as created by user1, but user1 doesn't exist anymore

Expected behavior
The CLI import command should have the same behaviour as the Web import tool