PR for foundation-2018: https://github.com/OpenNMS/opennms/pull/2123

PR for release-22.0.4 (and up): https://github.com/OpenNMS/opennms/pull/2124

The foundation-2018 version is all hand-includes in the relevant JSP pages.  The other one does proper webpack require and such.

I've implemented a basic class – OnmsDateFormatter – as well as an AngularJS filter (onmsDate) and a directive (that I never actually ended up having to use anywhere).  The directive just literally wraps around the date you want to format, like so: <onms-date>2018-04-15 05:29</onms-date> and it should do the right thing as long as moment.js can parse it.  The filter works similarly but is used in an AngularJS filter line... {{::item.pageTime | onmsDate.}}

PR: https://github.com/OpenNMS/opennms/pull/2083
=> closing PR since we will expose dateformat via REST endpoint, see https://issues.opennms.org/browse/NMS-10301

Render date in Angular JS: https://docs.angularjs.org/api/ng/filter/date