Issue #3424509 by godotislate, quietone, sorlov, smustgrave, alexpott, benjifisher: Update MigratePluginManager to include both attribute and annotation class

Revert "Issue #3424509 by godotislate, quietone, sorlov, smustgrave, benjifisher, alexpott: Update MigratePluginManager to include both attribute and annotation class"

This reverts commit c9d53fd4.

Issue #3424509 by godotislate, quietone, sorlov, smustgrave, benjifisher, alexpott: Update MigratePluginManager to include both attribute and annotation class

Issue #2756229 by mohit1604, RumyanaRuseva, quietone, heddn, 5to1: Improve destination missing exception message

Issue #2569805 by quietone, Jo Fitzgerald, mikeryan, joelpittet, heddn, Adita, Miguel.kode, iMiksu, tvb, maxocub, juancasantito, phenaproxima, alexpott, neclimdul, xjm: For Drupal migration, identify the source module

Issue #2225775 by vasi, quietone, phenaproxima, chx, penyaskito, mikeryan, esclapes, vprocessor, steinmb, Gábor Hojtsy, Marc Angles, bwinett: Migrate Drupal 6 core node translation to Drupal 8

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

Issue #2361093 by mikeryan, dawehner, Devin Carlson, benjy, phenaproxima: Add a rollback functionality to migrate

Issue #2321609 by benjy, dawehner: Fixed Provide a helpful message in case requirements are not met.

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

Migrate in core #2125717 by mikeryan, chx, marvil07, bdone, jessehs, mpgeek, BTMash, fastangel, mongolito404, Moshe Weitzman, eliza411, YesCT, dawehner, cosmicdreams