This reverts commit 2cf87103.

Issue #2120871 by andypost, Berdir, amateescu, vladan.me, Xano: Rename EntityListController to EntityListBuilder.

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

Issue #1996238 by sun, nod_, damiankloip, Wim Leers, longwave, alexpott, Xano, mdrummond, Mark Carver, Jeff Burnz, highrockmedia, joelpittet, et al: Replace hook_library_info() by *.libraries.yml file.

Issue #2198343 by damiankloip, longwave: Convert all usages of cache() and cache_invalidate_tags() procedural functions.

Issue #2165155 by Berdir, tim.plunkett: Change $entity_type to $entity_type_id and $entity_info to $entity_type/$entity_types.

Issue #2164827 by Berdir, Xano, tim.plunkett: Rename the entityInfo() and entityType() methods on EntityInterface and EntityStorageControllerInterface.

Issue #2168333 by tim.plunkett, EclipseGc, yched, fago: Ensure custom EntityType controllers can be provided by modules.

Issue #1649780 by effulgentsia, jibran, Wim Leers, nod_, hefox, joelpittet, kaare, BarisW, sun, rbayliss, Cottser, fubhy: Remove first/last/odd/even classes in favor of CSS3 pseudo selectors.

Issue #2005716 by tim.plunkett, msonnabaum, dawehner, alexpott, effulgentsia: Promote EntityType to a domain object.

Issue #732022 by vijaycs85, Wim Leers, dawehner, nod_, kscheirer: Drupal_add_tabledrag() still using drupal_add_(js|library)(), should return array for #attached.

Issue #1956448 by benjy, tim.plunkett, ed.hollinghurst, YesCT: Use the block instance title on the block admin listing.

Issue #2097537 follow-up by olli: Fixed yet another random failure in Drupal\block\Tests\Views\DisplayBlockTest->testBlockCategory().

Issue #2071019 by tim.plunkett, olli: Allow the block category for Views block displays to be edited.

Issue #2074509 by tim.plunkett, falcon03, mgifford, Xano: Fixed Add missing #title property to ensure form accessibility.

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

Issue #2067881 by ZenDoodles, mradcliffe: Fixed Search is missing from block admin UI after installation.

Issue #1995046 by pfrenssen, andypost, tim.plunkett: BlockListController doesn't call parent::getOperations() and so 'delete' is the default dropbutton operation.

Issue #1987952 by brantwynn, oriol_e9g, Freemantus, vuzzbox: Fixed Blocks are not rendered in order by weight.

Issue #1981144 by kgoel, tim.plunkett, disasm, vijaycs85, naxoc, stella, dawehner: Convert block_admin_edit() in block.admin.inc to the new form interface.

Issue #1986802 by yched: Rename PluginInspectionInterface::getDefinition() to getPluginDefinition().

Issue #1938898 followup by brantwynn, tim.plunkett, Cottser: Fixed Convert block theme tables to table #type.

Issue #1987066 by Kevin Morse, JohnAlbin, rteijeiro, echoz, ry5n: Rename files to match CSS file naming convention.

Issue #1927608 by EclipseGc, tim.plunkett, effulgentsia: Remove the tight coupling between Block Plugins and Block Entities.

Issue #1591806 by tim.plunkett, ryanissamson, jenlampton, Risse, psynaptic, Gábor Hojtsy, kmcculloch, pakmanlh, Rob Loach: Change block 'subject' so that it's called (admin_)label like everything else on the theme layer.

Issue #1913084 by tim.plunkett: Introduce a Form interface for building, validating, and submitting forms.

Issue #1913084 by tim.plunkett: Introduce a Form interface for building, validating, and submitting forms.

Issue #1903176 by tim.plunkett: Add a drupal_build_form() helper for using a method as the callback.

Issue #1871696 by tim.plunkett, xjm, sun, msonnabaum, EclipseGc: Convert block instances to configuration entities to resolve architectural issues.