feature #5908 Voter update (weaverryan)

This PR was merged into the 2.8 branch.

Discussion
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Voter update

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes
| Applies to    | 2.8+
| Fixed tickets | #5728

Commits
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31f6e3d Many tweaks thanks to a great review
5d0e6b2 tweaks thanks to Javier
a4c7d6e adding a section about calling isGranted() from within a voter
20cead6 Reworking the voter article for the new Voter class

Author: weaverryan