Option to ignore SSL certs

**Is your feature request related to a problem? Please describe.**

I am a paid software engineering professional working in crappy environments with net nannies that break HTTPS.

**Describe the solution you'd like**

An option in sync-settings to ignore SSL errors. Better yet, borrow the HTTP client from the main Atom client, so that global SSL settings automatically apply to this plugin.

**Describe alternatives you've considered**

This aberration is the sole reason I switched to VSCode. sync-settings was my world!

Start by locating the sync-settings code that performs HTTPS requests and compare it with Atom's HTTP client and global SSL settings. Define how an opt-in setting should be exposed in sync-settings, account for the security trade-off, and verify that default certificate validation and the requested ignore-errors behavior are both covered.

Written by the indexing model from the issue text.