create a pkg module for the command

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
add the pkg entry point in setup.py

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
create pkg module for debian
import it at the module level
all pkg_managers will take a list or a str

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
add pkg to centos distros

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
add zypper isntall and remove to suse distro

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
shortcut in fedora to use pkg from centos

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
add zypper support to pkg_managers

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
documented the new functionality for pkg

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
a wealth of tests for the pkg_managers module

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
Merge pull request #146 from alfredodeza/6964

creates a `pkg` sub-command to install/remove packages on remote hosts