Issue #2483781 by borisson_, rbayliss, cilefen, mitalimehta, joshi.rohit100: Move cache contexts classes from \Drupal\Core\Cache to \Drupal\Core\Cache\Context

Issue #2335661 by Wim Leers, pwolanin, dawehner, Fabianx, larowlan, catch, Berdir: Outbound path & route processors must specify cacheability metadata