Issue #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #2472147 by googletorp, anavarre, jaredsmith, bojanz: Standardize getter docblocks in node module

Issue #2226533 by martin107, filijonka, YesCT, Xano, jmolivas, Chris Dart, alexpott, tstoeckler, visabhishek | csg: Changes to the Language class due to the LanguageInterface (followup).

Issue #1976158 by Berdir | msonnabaum: Rename entity storage/list/form/render "controllers" to handlers.

Issue #2068333 by roderik, skipyT, pcambra, plach, Désiré, marcingy, peximo: Convert node SQL queries to the Entity Query API.