Patch 9.0.2/API changes

Summary
Patch 9.0.2 Shadowlands content patch.
 * TOC:
 * Diffs: wow-ui-source, BlizzardInterfaceResources

Notable changes

 * Help frame overhaul
 * now requires a hardware event
 * Shadowlands feature additions

Most significant changes took place in 9.0.1. See Patch 9.0.1/API changes for more information.