Add services to models.Application

[#78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>
populates EnvironmentVars when hitting app/summary endpoint

[#78294704]
add health_check_timeout to Application model

[#78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>
fake for generate_manifest.go

[#78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>
new package for generating manifests

[#78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>
new func to assert manifest orders in test

[#78294704]

Signed-off-by: Jonathan Berkhahn <jaberkha@us.ibm.com>
command create-app-manifest for generating manifest for pushed app

[finishes #78294704]

Signed-off-by: Simon Leung <leungs@us.ibm.com>