pjproject: remove usage of CFHOST and use POSIX api instead

This code seems bugguy when the iOS device is in LTE. IPv4 addresses for TURN
is not added, however it's successfully done for getaddrinfo.

From https://developer.apple.com/library/archive/documentation/NetworkingInternet/Conceptual/NetworkingTopics/Articles/ResolvingDNSHostnames.html
3 APIs exists for doing this resolution: "These functions should be used only
if you are writing portable code" and this is the case of pjsip. We should
avoid any platform specific code because it's hard to maintain.

Moreover, this code was included by https://trac.pjsip.org/repos/ticket/1246
I don't find any reference to this problem about local hostname, moreover,
local hostnames are not resolved by Jami, because we only pass IPs addresses
directly to pjsip, so this ticket doesn't apply for our codebase.

Change-Id: Iff6384eb3325d19f2c215dec953d794823adec51