This reverts commit cc84f390 - bad
commit message.

Issue #2014017 by jlbellido, alvar0hurtad0, undertext, benjy, penyaskito, LinL: Replace drupal_container() with Drupal::service() in the system module.

Issue #2049207 by dlu, blakehall, janstoeckler, ramlev, Moderate | Cottser: Replace .tpl.php with .html.twig in documentation.

Issue #1798732 by sun, Dean Reilly, mbrett5062, chx, westie, alexpott, juanolalla, Mark Carver, catch, jthorson, cam8001, Berdir: Convert install_task(), install_time() and install_current_batch() to use the state system.

Issue #2100329 by cosmicdreams: Use \Drupal instead of Drupal to make IDEs and static code analyse tools happy.

Issue #2095249 by mcjim: Change description text for admin/config/system/site-information to remove 'number of posts per page'.

Issue #1751194 by Cottser, mikl, effulgentsia, benjifisher: Introduce hook_theme_suggestions_HOOK() and hook_theme_suggestions_HOOK_alter().

Issue #1839318 by JohnAlbin, echoz: Added Replace drupal.base.css library with normalize.css for all themes.

Issue #2009674 by pplantinga, Samvel, dmitrii: Replace theme() with drupal_render() in system module.

Issue #1199946 by alexpott, fubhy, bojanz, steinmb, chx, catch: Fixed Disabled modules are broken beyond repair so the 'disable' functionality needs to be removed.

Issue #2089635 by tim.plunkett, disasm, larowlan: Convert non-test non-form page callbacks to routes and controllers.

Issue #2085907 by YesCT, Gábor Hojtsy: Ensure all configuration entities have an Edit/Configure tab by default.

Issue #1834002 by Gábor Hojtsy: Fixed Delete operations are all over the place. Remove tabs, provide title in routing.

Issue #1981368 by tim.plunkett, Crell, webchick: Convert all routes to 'module_name().foo_bar()' naming convention.

Issue #1987816 by pdrake, disasm, ParisLiakos, pguillard, vijaycs85, dawehner: Convert system_batch_page() to a new style controller.

Issue #1987814 by juampy, tim.plunkett, lliss, kushrohra: Convert system_admin_menu_block_page() to a new style controller.

Issue #1987818 by jlbellido, MattDanger, disasm, vijaycs85: Convert system_date_format_language_overview_page() to a new style controller.

Issue #1987810 by nick_schuch, dawehner, vijaycs85, tim.plunkett: Convert system_admin_config_page() to a new style controller.

Issue #1987808 by h3rj4n, vijaycs85, Dave.Ingram, tim.plunkett: Convert system_admin_compact_page() to a new style controller.

Issue #1934712 by dlu, alexpott, pplantinga, rbayliss, s_leu, Gaelan: Fixed Merge system.timezone config object into system.date.

Issue #2045923 by drupalrv, tim.plunkett: Replace all module_invoke_all() deprecated function calls in procedural code.

Issue #1987602 by glennpratt, juampy, pwieck, vijaycs85, dawehner, tim.plunkett, effulgentsia: Convert ajax_form_callback() to a new style controller.

Issue #2052389 by pwolanin: Fixed All elements added to the Request attributes should have a _ prepended unless they come from the path.