Add support for disabling prepending home with slash
Add support for disabling prepending home with slash

The env variable FPP_DISABLE_PREPENDING_HOME_WITH_SLASH can now be
used to tell fpp not to prepend a '/' to pathnames that start with
'home'. [0]

[0] https://github.com/facebook/PathPicker/issues/243#event-793450443

facebook/PathPicker,facebook/PathPicker,facebook/PathPicker,facebook/PathPicker