Issue #2947739 by Jaypan: Refactoring JS, separating three different integration types into separate scripts, so that they are only loaded if/when they are needed

Adding history API into thread inbox, to change the URL when threads are clicked in the inbox. Setting up the inbox update to be triggered after a new post is made. Adding .active-thread class to the active thread in the inbox. Removing .unread-thread class from inbox thread when a thread is viewed. Fixing cache tag invalidation overall for inbox

progressing on the users widget. Autocomplete results are now returned. Still need to add handlers to insert them into the existing framework, as well as show a display element

adding config admin area, and adding page to prep for uninstallation of the module, where all entities related to the module can be deleted

Setting up inbox to only show 5 threads, cleaning up some formatting, setting up similar code for different areas to follow same logic