Merge commit was d496655b

Issue #3016995 by Jon Pugh, tucho: Make file directories first class context properties: Sync files path directly if it is not in the site_path.

Issue #3016995 by Jon Pugh: Make file directories first class context properties: Fix path to imagecache.

Revert "Generate service.yml file to set cookie domains, and thus fix link construction on subdir sites."

This reverts commit b441a70e.

Issue #3016995 by Jon Pugh: Make file directories first class context properties: Sync back directoryes file_public_path and file_private_path.

Issue #2960237 by Jon Pugh: Sites on remote servers fail on Platforms that use git or composer, with Drupal in a subfolder. Allow other tools to alter the sunc path.

Revert "Issue #2754069: Replace drush_get_option('installed') with _provision_drupal_site_exists()."

This reverts commit ef408f09.

Issue #2838489: Don't write sites/all/drush/drushrc.php after provision-git-clone, so that drush make builds can happen afterwards.

This reverts commit 2840bc4a.

This reverts commit 4eb1ba7c.

This reverts commit b8ef181b.

'example.profile' files are no longer required for Drupal 8 profiles,
and are thus no longer reliable when searching for profiles on a platform.
Presumably, 'example.info.yml' will remain a requirement, so let's
check on that instead.