Move iOS app packaging to the cloud

This moves the signing and packaging of 
ios apps from the host that drives the device
to the cloud machine where the app is built.
This is in preparation of moving to Raspberry Pi 
hosts.


BUG=skia:5331

Change-Id: I4918272a6c734f5344351f0726b7721fde042234
Reviewed-on: https://skia-review.googlesource.com/9906
Commit-Queue: Stephan Altmueller <stephana@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
60 files changed