Add RHN subscription_manager module

The subscription_manager module acts as a wrapper to the command
'subscription-manager'.  The subscription-manager utility allows users
to manage RHN registration, subscription and yum repositories from the
Red Hat Entitlement platform.

Currently, this module supports the following sub-commands:
 * config
 * [un]register
 * subscribe
Updated examples and documentation
Update changelog
Merge pull request #3142 from mmoya/devel

Update changelog
Merge branch 'subscription_manager' of git://github.com/jlaska/ansible into devel
Fixup doc YAML
Update CHANGELOG
Simple zypper module to install, remove, or upgrades packages.
The rhnreg_ks module acts as a wrapper to the command 'rhnreg_ks'.  The
rhnreg_ks command allows users to manage registration to a Red Hat
Network (RHN) (e.g. rhn.redhat.com) server.  The moduel will also
interact with the specified RHN system via XMLRPC as needed.

Before proceeding with registration, the rhnreg_ks module will enable
the system to receive updates from RHN.  This involves enabling the
appropriate RHN yum plugin, as well as disabling an active
subscription-manager yum plugin.

Once enabled, the module will support the following operations:
 * configure
 * register
 * subscribe to custom child channels (see `rhn-channel` command)
 * unregister
Reorganize subscription_manager module.

Also ...
 * When unregistering, first unsubscribe from all content
Minor adjustments to subscription_manager and rhnreg_ks
Updates to the authorized_key documentation

* Clarified the meaning of 'user'
* Changed 'sshdir' to 'path' in the example
  * 'sshdir' is used internally in the module, but the argument is 'path'
* Made the capitalization consistent in the descriptions
BUG FIX: Add package name to the cmd.
Merge pull request #3145 from dirtyharrycallahan/f_zypper

Simple zypper module to install, remove, or upgrades packages.
Merge pull request #3148 from jlaska/rhnreg_ks

Add rhnreg_ks module
Update changelog
update changelog
Rename rhnreg_ks to rhn_register
Rename module
Update "added in" version in zypper, update doc name of rhn_register module.