Instance admin feature

[seb-kw]

No description provided.

[Hubtrick-Git]

Maybe we should also add a confirmation before revoking admin priviliges on a user?

[Hubtrick-Git]

Backend part is done, now the frontend needs some adjustments as well:

Org Dashboard

• Average Vulns per project stats got removed, remove it also in the web codebase
• Dtos got updated, have a look at statistics_dto.go in the backend to see what fields are there and what their name
  is. Match the frontend to the new variables
• A special case of this is the average remediation time stat. It now also comes with the average age of OPEN vulns
• Backend now caches statistics for 15 mins, we need a refresh button to force that if the user wants the updated stats. Query Param is called "forceRefresh" to force the refresh on request.
  see the backend for more information.