* Refactor common network shared and platform specific code into package (part-1)
As per proposal #76 refactor common network shared and platform specific
code into sub-package.
https://github.com/ansible/proposals/issues/76
* ansible.module_utils.network.common - command shared functions
* ansible.module_utils.network.{{ platform }} - where platform is platform specific shared functions
* Fix review comments
* Fix review comments
* Adding git_command module and its UT file
* Changing Author Name and removing 2 blank lines
* Removing blank lines
* Adding enos_config and its UT files
* Removing config module as I am allowed to have only module per PR
* Work on Ganesh's Review comments
* John Review Comments on enos_command.py
* Review comments of John
