Nethserver-arm 7.7.1908 images for testing

[davidep (Davide Principi)]

@davidep

YUM repositories of version 7.6.1810 are staying active for manual RPM uploads until 7.7.1908 Final is released.

I’m closing the uploads for 7.6 to packages.nethserver.org.

@mark_nl, before doing that we could release the nethserver-subscription-inventory package for ARM/7.6 upgrades to 7.7. Do you think it’s worth the effort?