Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2676222 by alexpott, johnrosswvsu: Move MigrationInterface out of the migrate\Entity namspace now they are plugins

(cherry picked from commit e0516e39)

Issue #2590993 by mikeryan, webflo, svendecabooter, dixon_, phenaproxima: Create stub entities with proper default values

Issue #2600538 by rakesh.gectcr, anil280988, justAChris, jhodgdon: Incorrect @file description in core/ classes - wrong namespace or class name

Issue #2504815 by neclimdul, phenaproxima, mikeryan: d6 to d8 migration throws integrity contraint warning with duplicate file paths

Issue #2534012 by phenaproxima, hussainweb, mikeryan: Move module-specific migration support into the file module

Issue #2417975 by phenaproxima, benjy, chx, neclimdul: EntityFile destination incorrectly assumes temporary files are absolute paths

Issue #2405337 by benjy: EntityFile destination doesn't handle temporary files when the source and destination are the same

Issue #2213451 by andypost, bdone, benjy, penyaskito, chx, claudiu.cristea, damiankloip, gregboggs, InternetDevels, jessehs, jhedstrom, marvil07, mikeryan, pcambra, Xano, YesCT: Update Migrate API in core