Issue #2067345 by Xano, jdillick, InternetDevels, bomoko | Berdir: Change EntityInterface type hints to NodeInterface where appropriate.

Issue #2078387 by Xano, andypost, twistor, splatio, InternetDevels, amateescu, Berdir, larowlan, vladan.me: Add an EntityOwnerInterface.

Issue #2042807 by tim.plunkett, pwolanin, ianthomas_uk, jhodgdon: Convert search plugins to use a ConfigEntity and a PluginBag.

Issue #535616 by jhodgdon, pwolanin, oriol_e9g, tgeller: Make Content Ranking settings for Search not say 'weights' to avoid confusion.

Issue #1786490 by Berdir, amateescu, damiankloip, Wim Leers, dawehner: Add caching to the state system.

Revert "Issue #1786490 by Berdir, amateescu, damiankloip, dawehner: Add caching to the state system."

This reverts commit 8ec847cc.

Issue #1998638 by damiankloip, dawehner, kim.pepper, cosmicdreams, alexpott, larowlan, Damien Tournoud: Replace almost all remaining superglobals (, , etc.) with Symfony Request object.

Issue #1998638 by damiankloip, dawehner, kim.pepper, cosmicdreams, larowlan, Damien Tournoud: Replace all remaining superglobals (, , etc.) with Symfony Request object.

Issue #2084279 by herom, andypost, David Hernández, dawehner, Xano: Remove plugin.manager.entity service in favor of entity.manager.

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

Issue #2086201 by tim.plunkett, pwolanin: Fixed Use PluginFormInterface instead of one-off form methods for search plugins.

Issue #2095641 by m1r1k: Use current_user() service instead of _account attribute to get user object.

Issue #2003482 by pwolanin, jhodgdon, kim.pepper, Nick_vh, tim.plunkett, jibran, Berdir, effulgentsia, alexpott: Convert hook_search_info() to plugin system.