Bug #2023211 “Run emulated riscv64 VMs on amd64” : Bugs : OpenStack Nova Compute Charm

[Impact] Since the OpenStack Yoga release is possible to run emulated architectures ( https://docs.openstack.org/nova/latest/admin/hw-emulation-architecture.html ), although riscv64 is not in the list of supported architectures. In the Launchpad build farm, we run a cluster of riscv64 virtual machines that deal with building riscv64 artifacts, including .debs for Ubuntu itself. We don't currently have hypervisor-capable riscv64 hardware to run these on, so we're using qemu system emulation...