docs: platforms: Clarify stance on third-party LTS efforts
docs: platforms: Clarify stance on third-party LTS efforts

Signed-off-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>
Reviewed-by: Pavel Hrdina <d4772d05997b8abf035041e3b4f4996380ea7e7a@redhat.com>

nertpinx/libvirt,jardasgit/libvirt,olafhering/libvirt,crobinso/libvirt,jardasgit/libvirt,nertpinx/libvirt,zippy2/libvirt,jardasgit/libvirt,olafhering/libvirt,zippy2/libvirt,libvirt/libvirt,jfehlig/libvirt,libvirt/libvirt,nertpinx/libvirt,olafhering/libvirt,jfehlig/libvirt,crobinso/libvirt,zippy2/libvirt,crobinso/libvirt,jardasgit/libvirt,libvirt/libvirt,jardasgit/libvirt,jfehlig/libvirt,zippy2/libvirt,nertpinx/libvirt,libvirt/libvirt,olafhering/libvirt,crobinso/libvirt,jfehlig/libvirt,nertpinx/libvirt