[Doc] Add sample/starter appveyor (+ other CI) configuration docs

[jacobq]

I know, I know, I should have had my project on CI from day 1, but for non-FOSS it costs money and there were politics to deal with (insert more lame excuses here). However, I am just now getting my ember-electron project setup on AppVeyor, and I'm sure I am re-inventing the wheel a bit. The docs here don't seem to talk much about setting up CI for ember-electron projects (arguably, it's not that hard & is out of scope), but I think it would be helpful to have a doc in the FAQ section that includes a collection of sample configuration files for various CI systems like AppVeyor, Circle, and Travis.

Would anyone out there be willing to share their configuration / notes here? If so, I'll gladly organize them into a doc and create a PR. I suspect that people will be especially interested in gotchas regarding code-signing & packaging for Mac & Microsoft app stores.

[jacobq]

Just noticed some info about this here: https://github.com/felixrieseberg/ember-electron/blob/master/docs/guides/ci.md

[jacobq]

I have one for AppVeyor from which I should be able to contribute a template. Any suggestions about where to put it? Somewhere near here in the docs?

[RobbieTheWagner]

@jacobq I think we should add a section for CI and code signing. I have mac signing working on GitHub actions, and hope to get Windows signing working soon. It would be nice to give everyone a quick way to get up and running on that.