Issue #2484619 by borisson_, Wim Leers, lauriii, larowlan, dawehner: Forum responses don't set cache tags

Issue #2408513 by MathieuSpil, Manjit.Singh, Vidushi Mehta, svendecabooter, LewisNyman, emma.maria: Refactor forum module CSS files inline with our CSS standards

Issue #2463009 by Wim Leers: Introduce CacheableResponseInterface: consolidate ways of setting X-Drupal-Cache-Tags/Contexts headers

Issue #2448605 by martin107, willzyx, tim.plunkett, klausi, dpopdan: Replace usages of drupal_get_destination() with the redirect destination service

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

Issue #2407765 by Wim Leers, borisson_: Wherever simple config is used to render output to end user, associate their cache tags

Issue #1853072 by stevepurkiss, larowlan, bjlewis2, mgifford, stefank: Remove forum_menu_local_tasks_alter() hack and instead add links in ForumController::build

Issue #2350877 by dawehner, Wim Leers, hussainweb: Deprecate/rename drupal_add_feed(), drupal_add_html_head(), drupal_add_html_head_link(), drupal_add_http_header(), and allow to be set declaratively in #attached.

Issue #2201659 by ocsilalala, larowlan | andypost: Fix serialization of the forum manager and dependency on current_user service.

Issue #2203407 by nod_, sun: Replace #attached library array values with provider-namespaced strings.

Issue #2110501 by tim.plunkett, pwolanin, tstoeckler: ControllerBase should implement ContainerInjectionInterface like FormBase.

Issue #2066535 by tim.plunkett, jsst, Berdir: Add EntityManagerInterface and stop typehinting with EntityManager.

Issue #2079477 by ParisLiakos: Fixed ForumManager and ForumController use ->translationManager->translate() instead of ->t().

Issue #1951268 by larowlan, nick_schuch, jibran, dawehner, alexpott, tim.plunkett: Convert /forum and /forum/% to new routing system, remove forum_forum_load(), forum_get_topics(), create new Forum service.

Issue #2057869 by dawehner, jibran: Provide an alias for 'plugin.manager.entity' called 'entity.manager'.

Issue #2057589 by smiletrl, tim.plunkett, alexpott, dawehner: Rename ControllerInterface to ContainerInjectionInterface.

Issue #1951278 by larowlan, tim-e: Create taxonomy term form controller for forum terms (ie not default) and use that for admin/structure/forum/edit/{forum|contain.