Feature: Custom DoH and DoT provider

[falahati]

Hey, Unfortunately, it seems that in my country all providers for DoH and DoT are either blocked by IP, poisoned by DNS, or rejected by DPI. So I, and I think many other people living in one of these greatest countries in the world can use the option to provide custom providers posted by ourselves or public ones that are less known. Specially custom DoH provider can be quite useful.

Thanks