[enh] Ability to add load such as FIO to the VMs

[wallnerryan]

Is your feature request related to a problem? Please describe.
The tests in the repo are great, but they lack the ability to add load to the VMs so that we can see these scenarios while active IO is taking place.

Describe the solution you'd like
Provide the ability for kubevirt-benchmark to run a workload, like FIO inside the VMs during these tests to add network and storage load to the system.

Describe alternatives you've considered
None

Additional context
Spoke to @dbhatnagar-px about this being a target enhancement. Adding the issue here so we can track it here.