Update references to source_config and target_config in application manifests

[brooksmtownsend]

Each reference to source_config and target_config, as well as the target: <target> structure are referring to deprecated fields in the Wadm application format. We should update each of these fields accordingly:

Source:

source_config:
  - name: foo

to

source:
  config:
    - name: foo

Target:

target: footarget
target_config:
  - name: foo

to:

target:
  name: footarget
  config:
    - name: foo