create nodes of different size

[bruggerk]

Allocate nodes depending on the queued job requirements. Eg memory and cores

This will require EHOS to pull information about flavors available in a openstack and try and use them in an optimal fashion.

Probably possible to set some min requirements in the configuration file so we don't end up with trying to spin up servers not meeting the minimum requirements. (This have been a "feature" before as it catches the openstacksdk out)