Issue #2556541 by mikeryan: Basic migration support (terms, users, nodes)

migration_templates/d5_filter_format.yml

migration_templates/d5_node.yml

migration_templates/d5_node_revision.yml

migration_templates/d5_node_setting_promote.yml

migration_templates/d5_node_setting_status.yml

migration_templates/d5_node_setting_sticky.yml

migration_templates/d5_node_settings.yml

migration_templates/d5_node_type.yml

migration_templates/d5_taxonomy_term.yml

migration_templates/d5_taxonomy_vocabulary.yml

migration_templates/d5_term_node.yml

migration_templates/d5_user.yml

migration_templates/d5_user_contact_settings.yml

migration_templates/d5_user_mail.yml

migration_templates/d5_user_role.yml

migration_templates/d5_user_settings.yml

migration_templates/d5_vocabulary_field.yml

migration_templates/d5_vocabulary_field_instance.yml

src/Plugin/migrate/builder/d5/Node.php

src/Plugin/migrate/source/d5/Field.php