Support Drupal aliases for event links in Views

1. Drupal supports URL aliases, e.g., configuring "my/content" to point to "node/1". When building a View in Drupal, links to nodes and similar content are transparently replaced with links to the alias instead of the native node path.

2. You can also create a URL alias in Drupal for a CiviCRM event with all the relevant query parameters, etc., and it works fine.

3. However, when you make a Drupal View out of CiviCRM Event data, and use the provided "Choose where to link this field" option to create a link, the native CiviCRM link is used, instead of the Drupal alias.

This ticket aims to add support for Drupal URL aliases for CiviCRM event links in Drupal views.

Note: we also thought about expanding the scope to support Drupal URL aliases for other CiviCRM entities in Views, or for all CiviCRM entities throughout CiviCRM (not just in Views), but after talking it over with Stuart (whose client is sponsoring this) and Coleman (core team), it seems this limited approach is the safest, and there's no compelling reason to expand the scope.