Unify and de-duplicate role creation information.

[lmaylein]

What this PR does / why we need it:

Some information about creating roles is duplicated, others were missing or not linked.

Which issue(s) this PR closes:

Closes none

Special notes for your reviewer:

I ask that you critically examine my English wording.
Please check also the new cross references because I'm not sure if the are rendered correctly

Suggestions on how to test this:

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

no

Is there a release notes update needed for this change?:

no

Additional documentation:

[pdurbin]

@lmaylein this is a nice cleanup. Thanks! I added some more cross links. I'd say this is ready for QA.

[pdurbin]

@lmaylein oh, one last thing. Next next time, please create a new branch instead of calling the branch "develop". We can work around this but having a new branch name makes it easier for us to update the branch. For details, please see this issue:

• Document how to update a "develop branch to develop branch" pull request  #9508

Thanks again!

[lmaylein]

@lmaylein oh, one last thing. Next next time, please create a new branch instead of calling the branch "develop". We can work around this but having a new branch name makes it easier for us to update the branch. For details, please see this issue:

Thanks for the link.