Add a new extension icon

[mirao]

The existing icon doesn't look well in the "Dark Modern" theme

nor with the the "Light modern" theme

[mirao]

Added a new icon created in Inkscape

Dark Modern:

Light Modern:

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How to test:

1. Change name of package in package.json to e.g. "mads-new` (so that it doesn't interfere with an existing public extension, otherwise you would get an old icon)

2. Package an extension (https://code.visualstudio.com/api/working-with-extensions/publishing-extension#packaging-extensions): $ vsce package

3. Install the extension locally:
   

4. Find the extension in list of extensions