add plan support for cloud server resize

[sgsullivan]

adds plan support for cloud server resize.

---
cloud:
  server:
    resize:
      - config-id: 0
        private-parent: "nvme-pp"
        uniq-id: "{{- .Var.uniq_id -}}"
        diskspace: 100
        vcpu: 3
        memory: 5000

lw plan --file plans/resize.yml --var uniq_id=057WU8

[dwburke]

lgtm

Pretty soon we should add a example_plans/ directory and put examples for each plan supported in there, but that doesn't have to be for this pr