Add -m memory option to setup-seed-vm

Add an option to increase the memory of the seed VM.

Defaults to 2G (same as configure-vm).

I've seen the seed VM run out of memory when provisioning
some underclouds... this should help in those cases.

Change-Id: I559ac235d8e4811f0ac44b545a69b90f0797bbad
Add -c cpus option to setup-seed-vm.

I'd like to give my seed VM a bit more firepower on occasion...

Change-Id: Ia7428813875bf313efa1cd75eee338add23249d7