Fix npm install and npm start for Node 12.x

[achekulaev]

npm install currently fails for all modern node verions.
There is no way to make it build for 13.x right now, since node-pty will not build for 13.x, so the most recent version it can build for is Node 12.x.
electron and electron-builder updates needed to support it.
Because of electron updates some code had needs updates to build.

[matthew-matvei]

@achekulaev Thanks very much for your input! I'll have a look into this (it's admittedly been a while since updating / building FreeMAN, and I'm having fun with balancing breaking (for me) dependencies).

It looks like I'll have to have a look at why AppVeyor isn't happy with it either.

Quick question: what's the reasoning for using a wildcard (*) for the versions of electron and electron-builder?

[achekulaev]

I find that usually latest electron version works just fine, and cases when it doesn't work just fine are not more often then the cases when old versions don't work fine (like this case for instance). So I just put asterisk for electron and consequently for builder.

I should note that despite these fixes do fix building and starting I could not get Freeman UI to actually work.

[matthew-matvei]

@achekulaev

Okay. I would generally prefer a more defined approach to dependency versioning, but that's not a blocker for me.

Looking at the AppVeyor build, it appears to fail at linting. Could you please run npm run lint and npm run test as described in the PULL_REQUEST_TEMPLATE.md? That should point you to some violations.

These mostly seem to be related to handling Promises now that Electron's API has been updated. The only non-trivial issue is the now asynchronous BrowserWindow.loadURL call in the FreemanWindow's constructor. I moved this call out into main/index.ts to sort out to properly await it in my debugging.

That may fix the immediate issue of the build, but I also currently have issues running the application (this PR is somewhat bringing this project out of the archive). That would need to be addressed, but that's not an issue your PR needs to handle.

[achekulaev]

I have addressed linting errors, but I cannot really get xvfb-maybe electron-mocha --renderer __tests__ to finish and don't have enough knowledge about electron-mocha to address it.