Default trackers file -> Improvements

[teddyrogers]

Tribler 8.1.0, the, "Default trackers file", feature has been greatly received and, in conjunction with, "Announce to all torrent trackers", torrents have been completing in record Tribler time.

One feature I would like to propose is having the option to download trackers lists directly from a website (https) when adding a torrent. If it fails to download the online trackers list, have a prompt, to revert to using the local (backup) copy if available.

Why the change? There are trackers lists on GitHub and other sites that kept up to date and are frequently checked (e.g. every hour). Local trackers lists could become stale and out of date if not updated frequently.

https://github.com/ngosang/trackerslist

Additionally, under the, "Trackers", tab could we have another button next to one of the two, "Add", buttons shown in the image below to either add the local trackers list and/ or the http/s link saved in the general settings page?