Issue #2803993 by mikeryan: migrate_example_advanced rest resources changed with D8.2.x

...stall/rest.resource.migrate_example_advanced_position.yml

.../rest.resource.migrate_example_advanced_variety_items.yml

...l/rest.resource.migrate_example_advanced_variety_list.yml

...st.resource.migrate_example_advanced_variety_multiple.yml

...ple_advanced_setup/migrate_example_advanced_setup.install

...anced_setup/src/Plugin/rest/resource/PositionResource.php

..._advanced_setup/src/Plugin/rest/resource/VarietyItems.php

...e_advanced_setup/src/Plugin/rest/resource/VarietyList.php

...nced_setup/src/Plugin/rest/resource/VarietyMultiFiles.php