Rename assistant categories according to new semantic everywhere

[philipperolet]

Ensure the new wording is used everywhere

• Default Assistant: cannot be deactivated or edited by anyone, provided by dust
• Company Assistant: New name for workspace
• Shared Assistant: Assistant that are published but not Workspace
• Personal Assistants: Unpublished assistants

[philipperolet]

Optionally, TBD before: rename in code "workspace" -> company, "published" -> shared, "private" -> personal, "global" -> default