[MM-46993] Implement CallsWidgetWindow (#2265)

* Initial implementation of CallsWidgetWindow

* Refactor + implement widget resizing logic

* Add tests

* Enable screen sharing

* Channel link

* Add more tests

* Move constants to common file

* Extract boundsDiff into util

* Set background color on initialization

* Fix channel link

* Support installations under a subpath

* Fix path, caching issues and pass title

* [MM-48142] Fix remaining call state issues in main window (#2349)

* Update widget URL to new format

* Slightly bump widget dimensions to account for border

* Fix call state on parent window

webpack.config.main.js

@@ -23,6 +23,7 @@ module.exports = merge(base, {
         modalPreload: './src/main/preload/modalPreload.js',
         loadingScreenPreload: './src/main/preload/loadingScreenPreload.js',
         urlView: './src/main/preload/urlView.js',
+        callsWidget: './src/main/preload/callsWidget.js',
     },
     externals: {
         'macos-notification-state': 'require("macos-notification-state")',