GitLab

* app: add code for macOS and Windows apps under 'app'

* app: add readme

* app: windows and linux only for now

* ci: fix ui CI validation

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Co-authored-by: jmorganca <jmorganca@gmail.com>

Enable both left and right click on the pop-up menu

- Updated setIcon method to include tooltip text for the system tray icon.
- Added NIF_TIP flag and set the tooltip text using UTF16 encoding.

Resolves: #6372

This focuses on Windows first, but coudl be used for Mac
and possibly linux in the future.