Specify rhcos_kernel_args per node type

[lukebrowning]

Master and worker nodes have different purposes. We should be able to specify kernel boot parameters for worker nodes apart from master nodes. For example, OCS worker nodes perform a lot of I/O which would benefit from CMA. Ideally, this could be specified for a set of worker nodes, since there may be application and ocs worker nodes, but for now it is sufficient to have a master and worker node split.

[lukebrowning]

It is not necessary to distinguish between different types of worker nodes, ocs and application, as I noted above, since the add node capability allows the project to be invoked multiple times. One could create the cluster with master and worker nodes for ocs, and then re-invoke the project to add application worker nodes.