qwtpolar, qextserialport, qgis, pikaur and gnucash removal

qwtpolar, qextserialport, qgis and gnucash were removed from and are no longer available on nexus.

The current alternative is to use the offical versions from the archlinux repo (qwtpolar, qextserialport, qgis, gnucash).

Previous Packages are available in the nexus-archive (qwtpolar, qextserialport, qgis, gnucash) for a limited time.