UI to monitor progress of experiments in realtime

STF Task Description:

• SHOULD: create a web interface to monitor the progress of the experiment in real time, and allow users to interrupt or restart either a single build or the whole workflow
  • Group many workflows / work requests that are part of the same experiment.
  • Provide a real time overview.

See: https://salsa.debian.org/freexian-team/debusine/-/blob/devel/docs/reference/devel-blueprints/experiment-workspaces.rst

Related:

• #697 (closed) Implement ephemeral groups
• #698 (closed) Implement expiration delay for workspaces
• #699 (closed) Add workflow to create an experiment workspace
• Document create_experiment_workspace task under Available server tasks, and create_experiment_workspace workflow under Available workflows (!1683 (merged))
• Add a can_manage permission on groups that also uses the per-user group role (!1686 (merged))