The GSettings schema path prefix for this applet
For applets that require unique instance configuration, the panel management must know where to initialise the settings within the tree. The path takes the form:
`$SETTINGS_PREFIX/{$UUID}`
As an example, the Budgie Menu Applet set's the `settings-prefix` to: `/com/solus-project/budgie-panel/instance/budgie-menu`.
This results in relocatable schemas being created at:
`/com/solus-project/budgie-panel/instance/budgie-menu/{$UUID}`