Add https.blindly-trust-domains to Arcanist
This allows users to specify that they want to implicitly trust their weird self-signed certificate without verification.
This can either be specified per user (which will make it apply every time the user runs arc, in any project):
arc set-config https.blindly-trust-domains '["example.mycompany.com"]'
...or added to a .arcconfig file (which will make it apply to every user who runs arc in that project):
"https.blindly-trust-domains" : ["example.mycompany.com"]
Depends on D7130.
Test Plan: Tweaked config and verified this setting sends HTTPSFuture down the right branch.
Reviewed By: btrahan
CC: hlau, aran
Differential Revision: https://secure.phabricator.com/D7131