fix: Fix save windows position on minimise on Linux. Add taskbar usage to Readme

* Update Readme with Usage of taskbar mode on macOS and Linux

* Remvoe custom context menu since was not working and we will use ALT version instead

* Rename processMoved to saveWindowPosition

* Fix by savingWindowPosition when user minimises Fether window so it restores to same position

* Change tooltip message to 'Click to toggle Fether window' since it is important on Linux as use must click the tooltip to open/close the Fether window

* Only disable taskbar mode on Windows