Add a warning to non-chromium browsers

[bsekachev]

My actions before raising this issue

• Read/searched the docs
• Searched past issues

CVAT works well in Google Chrome (where it is tested mainly). It also works in Firefox, but our users often uses Safari to work with CVAT, where the tool doesn't work correctly because of some Safari restrictions.

Possible Solution

Except of trying to fix Safari issues with a workaround we might add a warning message with recommendations to use another browser

Your Environment

• Git hash commit (git log -1): N/A
• Docker version docker version (e.g. Docker 17.0.05): N/A
• Are you using Docker Swarm or Kubernetes? No
• Operating System and version (e.g. Linux, Windows, MacOS): Mac OS