Description of problem:
Improve Satellite6 documentation by giving an option to the user to see instructions only for rhel 6/rhel7/both

Version-Release number of selected component (if applicable):
Satellite 6.2

How reproducible:
Always

Steps to Reproduce:
1. Go to https://access.redhat.com/documentation/en/red-hat-satellite/6.2/paged/installation-guide/chapter-6-upgrading-satellite-server-and-capsule-server


Actual results:
Although this comment is applicable to entire Satellite 6 documentation, for easy example, look at this section: - Section 6.2 - Step 12:

"12. Enable the new repository for Red Hat Satellite 6.2.

On Red Hat Enterprise Linux 6, run the following command:

# subscription-manager repos --enable rhel-6-server-satellite-6.2-rpms
On Red Hat Enterprise Linux 7, run the following command:

# subscription-manager repos --enable rhel-7-server-satellite-6.2-rpms"


Expected results:
If I am a customer who have just rhel 7 installations, I should be shown:

"12. Enable the new repository for Red Hat Satellite 6.2.

On Red Hat Enterprise Linux 7, run the following command:

# subscription-manager repos --enable rhel-7-server-satellite-6.2-rpms"


Additional info:
The user should be given an option to select his base OS - say 'rhel6' or 'rhel7' or 'both' in a dropdown - something like https://theforeman.org/plugins/#2.2Packageinstallation

Advantages:
* The user will be shown only the things which are relevant to his base OS.  This will improve readability and hence improve speed of installations.

Document URL: 

Section Number and Name: 

Describe the issue: 

Suggestions for improvement: 

Additional information: