gush push feature

                   
|Q            |A  |
|---          |---|
|Bug Fix?     |n  |
|New Feature? |n  |
|BC Breaks?   |n  |
|Deprecations?|n  |
|Tests Pass?  |n  |
|Fixed Tickets| #59 |
|License      |MIT|
|Doc PR       |   |
                   
- [x] move configure, update and labels command out of the flat namespace into a self
- [x] add syntax support gush git aliasing command
- [x] add push command