Port QEMU to vaccelrt API

[bchalios]

At the moment, QEMU is targeting the old runtime system API. The new runtime includes some API changes for which QEMU needs to be adapted if we decide we need it (cc @ananos, @papazof).

If we decide that this makes sense for our use-cases, we need to fix the API in QEMU and add support in this project. This requires:

1. Adding our QEMU fork as a submodule here
2. Create the script for building it
3. From the virtio-accel project create an action (and adapt the build script) to create linux images suitable for QEMU

[papazof]

An initial implementation of qemu w/ vaccelRT is at nubificus/qemu-vaccel@960dda0 (vaccelrt branch).

[bchalios]

@papazof what's the status of this?

[papazof]

@papazof what's the status of this?

The classify operation is implemented and working in the above branch. Should I try adding QEMU support in a branch here or do we need more from cloudkernels/qemu-vaccel ?