All the elements in docker app inspect command should be sorted

[silvin-lubecki]

Description
Running docker app inspect twice on the same package won't reproduce the same output:

$ docker app inspect
...
Services (5) Replicas Ports Image
------------ -------- ----- -----
db           1              postgres:9.4
results      1        5001  mikesir87/examplevotingapp_result
vote         2        5000  mikesir87/examplevotingapp_vote
redis        1              redis:alpine
worker       1              dockersamples/examplevotingapp_worker

Networks (2)
------------
backend
frontend

$ docker app inspect
...
Services (5) Replicas Ports Image
------------ -------- ----- -----
vote         2        5000  mikesir87/examplevotingapp_vote
redis        1              redis:alpine
worker       1              dockersamples/examplevotingapp_worker
db           1              postgres:9.4
results      1        5001  mikesir87/examplevotingapp_result

Networks (2)
------------
frontend
backend

Output of docker-app version:

v0.8.0-beta2

[ijc]

Networks etc are maps, so the randomness is explainable, but services is type Services []ServiceConfig, so I'm not sure how/why it is randomised. Nonetheless sorting it is easy...