LPS-32151 As a system adminstrator I can filter the visible set of users in the Private Messaging portlet
LPS-32151 source formatting
LPS-32151 Fix compile error? com.liferay.so.sites.util.SitesUtil != com.liferay.portlet.sites.util.SitesUtil. And, neither are available to this portlet. If it's used that much, we need to abstract it out to another method all together, but I'm leaving it in this (with duplicated code), for now, so that we can easily backport it.