Issue #2502621 by Pravin Ajaaz, hussainweb, Peacog, jhodgdon, ivanjaros: Replace implement notes with inheritdoc tag

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

Issue #2444231 by Wim Leers, nlisgo: Fix CacheableInterface so it makes sense (was: "Make Config objects & Entities implement CacheableInterface + add BubbleableMetadata::createFromCacheableObject()")

Issue #2286971 by znerol, Berdir, almaudoh, cilefen: Remove dependency of current_user on request and authentication manager

Issue #2222719 by effulgentsia, tim.plunkett, xjm, dawehner: Use parameter matching via reflection for access checks instead of pulling variables from request attributes.

Issue #2048223 by dawehner, ParisLiakos, herom, fubhy, damiankloip, vijaycs85, joelpittet, tim.plunkett: Add $account argument to AccessCheckInterface::access() method and use the current_user() service.

Issue #2063405 by dawehner, Wim Leers, Crell: Update all access checkers to use static::ALLOW/static::DENY/static::KILL.

Issue #1891052 by klausi: Fixed Protect write operations from CRSF by requiring an token (when using cookie/session-based authentication).