Summary:
The changes in this diff are sufficient to make this sequence work again:
```
./build electron-dev
bin/electron app/electron/runPrebuild.js
```
This brings up the local server within an electron window.
This is an unambitious diff, aimed at checking how rusty electron support had become. It does not revive Grist as a packaged electron app. The first substantial work needed would be to make the app aware of the local file system again, and think through how local files should be visualized and accessed now. In the past, there was a simple list of grist docs in a directory.
Test Plan: manual
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D3534
Summary: This moves enough server material into core to run a home server. The data engine is not yet incorporated (though in manual testing it works when ported).
Test Plan: existing tests pass
Reviewers: dsagal
Reviewed By: dsagal
Differential Revision: https://phab.getgrist.com/D2552
