upgrade staging to latest stable release

[gubuntu]

GeoNode 2.8
stable GeoSAFE
stable QGIS server etc.

ensure the documentation and Rancher catalog is clear to follow for doing a staging release

then deploy to production on geonode.kartoza.com when approved.

[gubuntu]

@boney-bun please do this

deploy staging onto geonode.kartoza.com, keeping all the content on that server. Configure it to accept staging.geonode.kartoza.com as well.

Then we will close down the old staging server