This commit cleans up the command constructors in an attempt to make the
codebase more uniform and approachable. This includes several refactors:
* Removed the FlagConstants - this makes the help messages and examples
significantly more readable without needed to compile and run
airshipctl
* Long help messages and examples are now constant
* Short, Long, and Examples all begin with a capitol letter
* Flag descriptions begin with a lowercase letter. This matches the flag
description for the builtin "help" flag, making formatting uniform for
all flags
* Removed redundant unit tests on non-leaf commands
This change also updates the documentation for the affected commands.
Change-Id: I8b9dcbfd9846b3deaab06dec17f80643dae78de9
9ffc305392