Add support for firecracker Hypervisor

[mcastelino]

Add support for firecracker in addition to QEMU as a supported hypervisor in Kata.

This will require a few changes and additions to Kata components

Runtime

• Making multiqueue optional for network interfaces
  network: Don't assume multiple queues support runtime#1027

• Adding support for the firecracker API

• Actual implementation of the hypervisor interface

• Adding support to boot from disk (vs nvdimm or initramfs)

• Adding support for virtio-mmio type devices

• Supporting gRPC based copy of files from host to VM

Kernel

• Updating the Kata kernel configuration

Packaging

• Packaging of the rootfs as a disk in a firecracker friendly format
• Supporting a debug console over vsock (to aid debugging)

Agent

• Adding support for virtio-mmio type devices in the runtime
• Supporting gRPC based copy of files from host to VM

[mcastelino]

#272

[mcastelino]

kata-containers/runtime#1026

[mcastelino]

kata-containers/runtime#1028

[mcastelino]

Tracking this in the runtime. Closing it here to avoid confusion.