Starters based on spring-cloud

  - spring-boot-starter-cloud-cloudfoundry is a starter for CloudFounry
  - spring-boot-starter-cloud-heroku is a starter for Heroku
  - spring-boot-starter-cloud-localconfig is a starer for local config (test platform)
  - spring-boot-starter-cloud-multiplatform includes all of the above
  - spring-boot-starter-cloud is a starter without a platform (user must add a platform-specific
      dependency)

Fixes #1325