Another change to make the plugin install on stock unraid without
other plugins installed.

Finally had the time to test on stock unraid without other installed
plugins. The install problem was fixed by moving the icon files to
fully reside on github. They will be downloaded on first install.

Sadly I now noticed another problem. My selfbuild proftpd with
included mysql support requires a sql-lib as dependency. I missed
that, as I had this installed before writing this plugin. So still
work to do.