Rename install_abrt task and improve it

Rename install_abrt task to setup_abrt as the install tasks are for
product installation. Do some improvements related to comments on #44.
Merge pull request #47 from elyezer/improve-setup-abrt

Rename install_abrt task and improve it
Sphinx docs implementation
Merge pull request #48 from sthirugn/docs

Sphinx docs implementation
Make docs build with 0 errors

Comment out an unnecessary configuration file option. This makes Sphinx emit
zero warnings when building documentation.

Make the configuration file flake8 and pylint compliant.
Split environ variables for OS name and version.

Only the ``subscribe`` method really requires the environment variable
that contains the name for the distribution where Satellite 6 will be
installed. Since only **RHEL** is supported for Satellite 6 installs, I
think it is safe to change the expected environment variables to be the
following:

* ``OS_NAME``: most of the time this should be ``rhel``
* ``OS_VERSION``: Major version for one of the supported versions
  of **RHEL**; in this case 6 or 7.
Merge pull request #52 from omaciel/split-distro-variable

Split environ variables for OS name and version.
Run setup_abrt task after upstream install

The setup_abrt will run only on RHEL7.

Also improve the setup_abrt docstring to provide information about its
current availability only on RHEL7.

Closes #49
Merge pull request #50 from elyezer/abrt-rhel7

Run setup_abrt task after upstream install
Add distro_info task

The distro_info task will inspect /etc/redhat-release in order to
discover the distro and version.
Update distro information to use distro_info task

Use distro_info instead of asking for OS_NAME and OS_VERSION environment
variables.
Merge pull request #54 from elyezer/distro-info

Add distro_info task
Merge pull request #51 from Ichimonji10/clean-build

Make docs build with 0 errors
Updated Docs to reflect new environ variables.

The environmental variable ``DISTRO`` is no longer valid. Instead,
please use ``OS_NAME`` and ``OS_VERSION``. For most tasks, if you don't
provide a value for ``OS_VERSION``, then tests which make use of this
variable will default to the value of ``7``.
Merge pull request #53 from omaciel/updste-docs

Updated Docs to reflect new environ variables.
Make sure the system packages are updated

Run yum update after enabling repositories.
Merge pull request #56 from elyezer/update-packages

Make sure the system packages are updated