Genome::Process

`Genome::Process` serves as a holder of metadata related to commands that run workflows.  It is in some ways a stripped down `Genome::Model::Build`.  It will make possible `genome model build view` like views for things such as `Genome::VariantReporting` or the data importing commands.
I'm torn on this.  I did it this way because the `owner` on `Disk::Allocation` is not unique, so you cannot enforce a one-to-one relationship.  I agree, however, that it is denormalized in the sense that the owner will obviously be identical to the `Genome::Process` with that `disk_allocation_id`.