Remove use of @electron/remote

[apetresc]

We use @electron/remote to bridge the main and renderer Electron processes, exclusively (as far as I can tell) to query the settings.json from within the renderer. This is considered very bad now, and in Electron 14+ it's gone and needs all sorts of hacks to patch back in.

We should just redesign the way we communicate settings to the browser. This needs some research and a slightly new design, but should be relatively straightforward since it is, at the end of the day, just a static object.