New base class(es) for link field handlers in Views

Views now automatically provides links for every entity type, which means that you have an view /edit as well as delete link available.

API-wise field handlers were changed:

A couple of new base classes were introduced:

• Drupal\views\Plugin\views\field\LinkBase should be extended by all field handlers providing an internal link.
• Drupal\views\Plugin\views\field\EntityLink should be extended by all field handlers implementing additional entity link templates, e.g. the content translation link (which is now added generically to Views data by the Content Translation module).

One of the main reasons to use these new base classes is that they provide automatic access control for the destination route, thus links will be automatically hidden if the user cannot access the target page.