Display description of model & model versions

Refs https://gitlab.com/teklia/requests/-/issues/844

The backend serves these description in RetrieveModel & RetrieveModelVersion.

We need to display them in:

• worker run details (only when present)
• model browser page:
  • model description on top of page
    • add a title with model name
    • set description right below
  • model version description as a new modal, enabled by an action "Details" on the right side of each line
    • display model version details like on the worker run