Create default migration templates

Do we need any special handling here?

Based on how migrate works, I'd expect more that we have to provide sources and processors to convert the data to the right format, but there's not really something special about the destination at the moment?

It is very easy, indeed. You do not need an additional migration, Entity does the job.

In my migrate.migration.{migration_id}.yml I simply added this processing and everything works :)

process:
  # Media bundle.
  bundle:
    plugin: default_value
    default_value: image
  # Use image title as media name.
  name: title
  status:
    plugin: default_value
    default_value: 1
  # Add description.
  field_description: caption
  'field_description/format':
    plugin: default_value
    default_value: 'basic_html'
  # Add image to media entity.
  'field_image/target_id':
    plugin: migration
    migration: article_images
    source: filename
  'field_image/title': title
  'field_image/alt': alt
destination:
  plugin: entity:media

Related: I wrote a Scald Atom source for a custom migration project, so I contributed it over at #2772129: Scald Atom migrate source.

@stBorchert, would you mind telling witch Migrate source plugin did you used?

@manu manu: We used a custom source plugin for Yaml files (https://www.drupal.org/sandbox/stborchert/2808617).
Note that the source shouldn't matter here (as long as it provides the correct values ;) ).

Thanks @stBorchert :-)

Linking in #2906878: [Meta] Support for D7 -> D9 contrib migrate