Backport: Use client-side cache tags & caching to eliminate 1 HTTP requests/page for in-place editing metadata, introduce drupalSettings.user.permissionsHash

#2005644: Use client-side cache tags & caching to eliminate 1 HTTP requests/page for in-place editing metadata, introduce drupalSettings.user.permissionsHash should be backported to Drupal 7, to keep the JS code identical, and to give the D7 backport the same front-end performance improvement.