Upgrate CF CLI to support variable substitution

[o-orand]

Is your feature request related to a problem? Please describe. As operator, I want to able to leverage new CF CLI syntax, see https://github.com/orange-cloudfoundry/paas-templates/issues/71

and https://docs.cloudfoundry.org/devguide/deploy-apps/manifest-attributes.html#variable-substitution

Given a vars.yml file such as

instances: 2
memory: 1G

Given an app manifest file using the following format: ((VARIABLE-NAME)) such as :1234:

---
applications:
- name: test-app
  instances: ((instances))
  memory: ((memory))
  buildpacks:
  - go_buildpack
  env:
    GOPACKAGENAME: go_calls_ruby
  command: go_calls_ruby

and CF CLI invoked with cf push --vars-file /PATH/vars.yml then CF CLI pushes an interpolated manifest file.

[poblin-orange]

use 6.38 with cf-deployment 1.40

[poblin-orange]

use 6.41 with cf-deployment 2.7 paas templates 36

[gberche-orange]

Potentially useful in https://github.com/orange-cloudfoundry/cf-services-bench/issues/2

[poblin-orange]

bosh deployment with scripting release can compensate this