Address remaining issues for v2.2 release #20

These changes address the two remaining issues for the v2.2 release, issues #8 and #11. Additionally, they move the config file location into AppData and add artifacts of the release executable to the build workflow to ease testing.

Summary of included commits:

- Remove "Rescale pointer between screens" option
- Save config file to AppData instead of executable directory
- Document settings retention
- Upload executable artifact in build workflow

Show unsnage counter when hovering on icon

Tray icon support

Update Readme.md.