Move wisski instance code to separate package

internal/wisski/instances/barrel/wisskiutils/settings_php_get.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+# settings_php_get.sh name
+# Gets the 'settings_php_get.php' setting 'name' as json-encoded value, or null when it does not exist.
+
+NAME=$1
+
+if [ -z "$NAME" ]; then
+    echo "Usage: get_settings_setting.sh NAME"
+    exit 1
+fi;
+
+echo "$NAME" | drush php:eval '
+  use \Drupal\Core\Site\Settings;
+  $name=trim(file_get_contents("php://stdin"));
+  echo json_encode(Settings::get($name));
+';