Feat: custom (sub)domain setup

[humphd]

When doing various web-related work, you often need a custom domain. Often this is needed in order to setup SSL for API security between client/server.

I want a way to manage this easily for projects that Seneca people are working on.

If this extension has the concept of someone being a "Seneca" dev, surely we've authenticated them with SSO or via email or the like. If so, we know their username (whatever@myseneca.ca or whatever@senecacollege.ca). Imagine that we buy one or more domains, something.ca and we make it really easy for a user to create whatever.something.ca (personal sub-domain) and also project1.whatever.something.ca (per-project sub-domain).

Maybe sub-domains expire in a certain amount of time, maybe they don't? Not sure.

It would also be nice to help automate the SSL/Let's Encrypt setup to help people get certificates, though this might be a separate issue.