Add support for zoomFactor and globalVars Draw.io configuration options

[micellius]

This PR adds the ability to configure standard zoomFactor and globalVars Draw.io configuration options with hediet.vscode-drawio.zoomFactor and hediet.vscode-drawio.globalVars VSCode settings respectively.

The configuration options will solve the following issues:

• 301 now it will be possible to configure trackpad sensitivity same way as in desktop app

  {
  "hediet.vscode-drawio.zoomFactor": 1.05
  }

• 298 now it will be no need to use deprecated hediet.vscode-drawio.local-storage, and the arbitrary Draw.io plugin configuration may be stored in more idiomatic Draw.io way.

  {
  "hediet.vscode-drawio.globalVars": {
    "somekey":{
      "somedeeperkey": false
    }
  }
  }

  Within the custom Draw.io plugin code the values will be accessible same way as currently within desktop app - with Editor.globalVars:

  Draw.loadPlugin(function (ui) {
  ...
  Editor.globalVars?.somekey?.somedeeperkey // false
  ...
  });

In the issue discussion of #301 you mentioned that

I'm open for a PR that introduces a new VS Code setting and forwards it to draw.io.

So, I hope there is a chance that you can merge this PR.

I tested manually both configuration options on macOS VSCode 1.65.2 in development mode and as vsix, and they are working as I expected. For the moment of writing this, there are ~34 more Draw.io common (without Confluence or Quip extras) configuration options not supported in VSCode extension, but I haven't found any open GitHub issue that asks for them (except 2 mentioned above), so I didn't add them. I've taken the description of configuration options from official Draw.io docs (see Format section), but I can change them to something different, if you think it will make more sense.

Thanks for the great VSCode extension! Let's keep making it even better 😉

[hediet]

Awesome, change looks good!

Can you please rebase on main and update the changelog? Please change the heading ## [1.6.5-alpha.1] to ## [1.6.5-alpha.2] (overwrite the existing), so an insiders gets published automatically when merging this PR.

Thank you!

[micellius]

Changes from upstream incorporated, changelog updated, linting issues fixed.

[hediet]

Should be available in the insiders release in a couple of minutes.