Add e2e test for must-gather

[marioferh]

Add e2e test for collectMachineinfo #781

[ffromani]

we should exercise indeed the collection of machineinfo, but we should have e2e tests for must-gather in general. It's fine to start exercising the newer code path (machineinfo).

[marioferh]

https://github.com/openshift/cluster-node-tuning-operator/pull/365/commits