handle case where the proxy is geo-locked but not the server that host invidious

[unixfox]

Some videos will work on the server that host invidious but not on the external proxy, this is an issue because the videojs player will try to infinitely try to load the video due to the error returned by the proxy.

Solution:
Have a separate web server that check the health of the proxies, if the video is available in the location. Then redirect the request to the least loaded server.

This web server can also be anycast (fly.io) in order to redirect to proxies close to the user.