Update message pinning to show up on the tab list with a few options to allow/disallow it and whether to allow anyone to pin messages

This change also alters how edits are displayed both for sequential
and non-sequential messages.

See #1357

This comes in the form of the user's avatar, along with a hover
title that shows username and edit time. As a side note, this
requires us to start saving 'editBy' id as part of message updates.

This has been tested with all 4 of the current avatar methods.

fixes #824

Added user method for searching users from same domain

Note that this also makes a minor tweak to scope of "if description"
check in admin.html, that is more correct.

This change also swaps out the settings group display from <h3>
to <p> for a better look and feel.

This should cut down on the redundant i18nDescription declarations
by allowing developers to utilize the default key + "_Description"
convention in the i18n/ files for settings and setting groups

Example: setting LDAP_Enable will look for the LDAP_Enable_Description
key unless it's explicitly overriden.