Issue #3483050 by mstrelan, nicxvan: Add int return type to all hook_update_last_removed implementations

(cherry picked from commit 3d350b03)

Issue #3483057 by mstrelan, bbrala, smustgrave: Add void return type to all hook_install and hook_uninstall implementations

Issue #3290810 by Spokje, catch, dww, longwave, alexpott: Remove updates added prior to 9.4.0 (9.4.4 for ckeditor) and add 9.4.0 database dumps

Issue #3049048 by danflanagan8, ndobromirov, mglaman, bbrala, alexpott, Wim Leers, gabesullice: Invalid JSON:API responses when maintenance mode is on

Issue #3087644 by jibran, Berdir, alexpott, longwave, Wim Leers, amateescu, catch, xjm, larowlan, dpi, quietone: Remove Drupal 8 updates up to and including 88**

Revert "Issue #3087644 by jibran, Berdir, alexpott, longwave, Wim Leers, amateescu, catch, larowlan, dpi, quietone: Remove Drupal 8 updates up to and including 88**"

This reverts commit 136f0550.

Issue #3087644 by jibran, Berdir, alexpott, longwave, Wim Leers, amateescu, catch, larowlan, dpi, quietone: Remove Drupal 8 updates up to and including 88**

Issue #3068275 by Wim Leers, alexpott, shimpy, gabesullice, xjm: Add status report message about JSON:API's read-only mode

Issue #2843147 by Wim Leers, e0ipso, gabesullice, dagmar, xjm, effulgentsia, webchick, dww, Berdir, dawehner, colan, mgalalm, govind.maloo, das-peter, jludwig, ndobromirov, martin107, abhisekmazumdar, nuez, catch, amateescu, pwolanin, mallezie, borisson_, jibran, voleger, plach, GeduR, Grimreaper, apupiales, Sutharsan, RenatoG, michaellander, sergesemashko, dbt102, hampercm, dremy, rpayanm, chriscalip, tstoeckler, keopx, skyredwang, Spleshka, RajeevK, matthew.perry, kaysenlau, jazzdrive3, dsdeiz, ebeyrent, acbramley, deviantintegral, samuel.mortenson, DamienMcKenna, mohit_aghera, ibustos, dpolant, garphy: Add JSON:API to core as a stable module