update apply/scale transform config for ordering and flexibility

[edaniszewski]

This PR:

• changes the device config
  • removes instance ScalingFactor config
  • removes instance Apply config
  • adds Transformers config which allows specifying multiple scales/apply transforms in an ordered list
• adds and updates tests

With this, a config snippet like:

devices:
- type: foo
  instances:
    - info: Device 1
      scalingFactor: 0.1
      apply:
        - FtoC

becomes

devices:
- type: foo
  instances:
    - info: Device 1
      transforms:
      - scale: 0.1
      - apply: FtoC

this allows you to specify order because it is a list, so if you want to apply before scale,

devices:
- type: foo
  instances:
    - info: Device 1
      transforms:
      - apply: FtoC
      - scale: 0.1

fixes #449