Issue #2711099 by heddn, Jo Fitzgerald, edysmp, edgewl2, alexpott, Charlotte17, mikeryan, masipila, quietone, maxocub, phenaproxima: Categorize migrations according to their type
Issue #2917883 by quietone, TR, Jo Fitzgerald, masipila, phenaproxima: Rename 'migration_templates' directories in core modules to 'migrations'
Revert "Issue #2560795 by mikeryan, phenaproxima, penyaskito, willwh, benjy: Source plugins have a hidden dependency on migrate_drupal" This reverts commit 89815ba3.
Issue #2560795 by mikeryan, phenaproxima, penyaskito, willwh, benjy: Source plugins have a hidden dependency on migrate_drupal
Issue #2463909 by phenaproxima, mikeryan: Migrations should support non-installed default configurations (templates)
Issue #2460529 by alexpott, chx, phenaproxima: Migrations need to use the configuration entity dependency system
Issue #2466797 by mikeryan, benjy: Rename migration_groups key to avoid confusion with MigrationGroup support
Issue #2358269 by Gábor Hojtsy: Migration bugs in block visibility, field overrides, cron, maintenance settings and form modes found by configuration schema checking