Revert "Issue #2500513 by svendecabooter, phenaproxima: Upgrade path for Shortcut 7.x"

core/modules/migrate_drupal/src/Tests/Table/d7/MenuLinks.php

...modules/migrate_drupal/src/Tests/Table/d7/ShortcutSet.php

...es/migrate_drupal/src/Tests/Table/d7/ShortcutSetUsers.php

core/modules/shortcut/migration_templates/d7_shortcut.yml

.../modules/shortcut/migration_templates/d7_shortcut_set.yml

...es/shortcut/migration_templates/d7_shortcut_set_users.yml

...tcut/src/Plugin/migrate/destination/EntityShortcutSet.php

...rtcut/src/Plugin/migrate/destination/ShortcutSetUsers.php

...odules/shortcut/src/Plugin/migrate/source/d7/Shortcut.php

...les/shortcut/src/Plugin/migrate/source/d7/ShortcutSet.php

...hortcut/src/Plugin/migrate/source/d7/ShortcutSetUsers.php

.../shortcut/src/Tests/Migrate/d7/MigrateShortcutSetTest.php

...tcut/src/Tests/Migrate/d7/MigrateShortcutSetUsersTest.php

...les/shortcut/src/Tests/Migrate/d7/MigrateShortcutTest.php

...sts/src/Unit/Plugin/migrate/source/d7/ShortcutSetTest.php

...rc/Unit/Plugin/migrate/source/d7/ShortcutSetUsersTest.php

.../tests/src/Unit/Plugin/migrate/source/d7/ShortcutTest.php