Issue #2960013 by quietone, Jo Fitzgerald, mikeryan, alexpott: i18n menu links translation in wrong directory

Issue #2912348 by maxocub, Jo Fitzgerald, masipila, heddn, phenaproxima: Handle entity_references related to Drupal 6 and 7 node translations with different IDs

Issue #2687843 by quietone, heddn, Jo Fitzgerald, alexpott, piggito, mallezie, mikeryan, xjm, phenaproxima, benjifisher, webchick, Gábor Hojtsy, masipila, benjy, abhishek-anand, catch: Add back incremental migrations through the UI

Issue #2914974 by quietone, rakesh.gectcr, maxocub, heddn, Jo Fitzgerald, Yogesh Pawar, masipila, phenaproxima, jhodgdon, Gábor Hojtsy, larowlan, neclimdul: Migrate UI - handle sources that do not need an upgrade