Improve how alerts and infos are displayed.
Update the tests results when a new agent is selected.

This commit necessited some refactoring and now the code is a bit
cleaner but there is still room for improvement.
Agents list in test page now display currently running agents.
Add a divider before "All agents" in the dropdown menu.
Save the displayed agent(s) on the test page.
Improve display of saved tests results file path.
Fix git repo detection.
Further improve which saved tests results path is displayed to the user.
Merge remote-tracking branch 'origin/topic/bf_ui_improvements' into develop

* origin/topic/bf_ui_improvements:
  Further improve which saved tests results path is displayed to the user.
  Fix git repo detection.
  Improve display of saved tests results file path.
  Save the displayed agent(s) on the test page.
  Add a divider before "All agents" in the dropdown menu.
  Agents list in test page now display currently running agents.
  Update the tests results when a new agent is selected.
  Improve how alerts and infos are displayed.
Release version v0.2.3-rc031.