Adding features related to "Fragment"

[mehdiirh]

Hi.

First of all, thank you for your great work.

There are three features about fragment, that need to be added in all v2ray clients, including v2rayNG.

• Add support for fragment configuration per link
  Fragmentation should be configured per link, not generally for the whole app, as some ISPs need fragmentation and other not.

• Add support for fragment configuration in v2ray links
  This feature is recently added in v2box (iOS client). This way you can configure fragmentation automatically.
  It should be in a standard format within all clients:
  vless://UUID@server.com:443?allowInsecure=1&type=ws&fragment=60-150,7-15,tlshello (Lenght,Interval,Packets)

• Add support for JSON in subscription links
  Subscription links should handle JSON configurations, including b64 encoded ones. if a subscription returns a JSON or a b64 encoded JSON ( or a few b64encoded regular links + b64 encoded JSONs, with \n separated ) it should be processed. Because fragmentation configurations ( or other settings like routing and DNSes ) uses this type.

Regards