Fix auth documentation, and a frontend regex

[msm-cert]

Your checklist for this pull request

• I've read the contributing guideline.
• I've tested my changes by building and running mquery, and testing changed functionality (if applicable)
• I've added automated tests for my change (if applicable, optional)
• I've updated documentation to reflect my change (if applicable)

What is the current behaviour?
Current behaviour related to anonymous users is confusing.

What is the new behaviour?
The documentation was fixed and some obsolete fragments were removed.
The documentation was updated, and the current behaviour was made more clear.
A regex in the config submission was fixed to allow the nobody role.

Fixes #422