Integrate Cobra for enhanced CLI experience

[sharepointoscar]

https://github.com/spf13/cobra

Benefits

Cobra provides:

Easy subcommand-based CLIs: app server, app fetch, etc.
Fully POSIX-compliant flags (including short & long versions)
Nested subcommands
Global, local and cascading flags
Easy generation of applications & commands with cobra init appname & cobra add cmdname
Intelligent suggestions (app srver... did you mean app server?)
Automatic help generation for commands and flags
Automatic help flag recognition of -h, --help, etc.
Automatically generated bash autocomplete for your application
Automatically generated man pages for your application
Command aliases so you can change things without breaking them
The flexibility to define your own help, usage, etc.
Optional tight integration with viper for 12-factor apps