docs: Add entry for ZStack to apps page
docs: Add entry for ZStack to apps page

Signed-off-by: Shuang He <7ff8f089777ddd3e2448f6622a5e20630247134e@zstack.io>
Signed-off-by: Erik Skultety <2c14d38fa47c8799f1b9c16280abe27f8edfec6e@redhat.com>

nertpinx/libvirt,olafhering/libvirt,libvirt/libvirt,crobinso/libvirt,andreabolognani/libvirt,eskultety/libvirt,eskultety/libvirt,jardasgit/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,eskultety/libvirt,olafhering/libvirt,fabianfreyer/libvirt,libvirt/libvirt,jardasgit/libvirt,libvirt/libvirt,nertpinx/libvirt,eskultety/libvirt,jardasgit/libvirt,jardasgit/libvirt,andreabolognani/libvirt,libvirt/libvirt,crobinso/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,jfehlig/libvirt,zippy2/libvirt,zippy2/libvirt,eskultety/libvirt,olafhering/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jfehlig/libvirt,jfehlig/libvirt,zippy2/libvirt,jfehlig/libvirt,crobinso/libvirt,nertpinx/libvirt,zippy2/libvirt,olafhering/libvirt,jardasgit/libvirt,andreabolognani/libvirt,crobinso/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt