Arcanist configuration: DevCentral is now HTTPS

Summary:
DevCentral is now served from HTTPS.
This is enforced with a 301 redirection from HTTP to HTTPS.

As such, Arcanist configuration has to be updated to use the correct
certificate or API token, https://devcentral.nasqueron.org.

Ref T918

Test Plan: arc which

Reviewers: dereckson

Maniphest Tasks: T918

Differential Revision: https://devcentral.nasqueron.org/D504