Implement frame-less about dialog with 'OK/Close' button

Current implementation for About dialog is using modal BrowserWindow and it is results in different look on windows and macOS. On windows it has titleBar which is white and configured in widows appearance settings. On macOS it is implemented as Sheet and frame-less without any buttons and disabled Cmd+W shortcut.

To make it look the same we can explore frameless window under Windows and add normal OK or Close button to provide the way to close the Window.