This changes restarts to drop the 'release' part that currently gets triggered, which also helps reduce the possibility that a new image layer will be added due to predeploy deploy triggers.
Note that the old method essentially halfway-rebuilt the app (which was what added the extra layer). This refactor removes that, which is a bc-break.
Additionally, scaling processes will result in deploying _only_ restarting the processes being scaled.
Closes#2184
Not all properties can be set globally, and the "appName" in the global case is currently defaulted to `--global`. This is okay because domain label names cannot start with hyphens, and all app names must be valid domain label names.
There are other places in the codebase that currently act on all apps or could benefit from being able to do so. Being able to run `common.RunCommandAgainstAllApps()` and get that for free will be a boon to implementing this functionality elsewhere.
