Use potentially weak keys generated using low security random sources (to avoid running out of entropy on the dispatcher) and generate the lava public and private key on a per job basis.

This support is intended for a secondary connection which will run a VM inside the test action and will need to copy content into that VM. Copy the public key into the guest deployment, use the existing support to copy the private key into the host deployment. Add the public key to the authorized_keys list on the guest.

Migrated from https://projects.linaro.org/browse/LAVA-517