Added drivers_config_path to Multibackend.ini

- It is optional configuration specifying the path to the drivers configurations relative to vufind config dir -- omit to locate those in vufind config dir -- it also could be an absolute path

config/vufind/MultiBackend.ini

@@ -4,6 +4,11 @@
 ; from the [Drivers] section below if set -- omit to have no default driver)
 ;default_driver = "instance1"
 
+; (Optional) the path to the driver configurations relative to VuFind config
+; dir -- omit to locate those in VuFind config dir -- it also could be an
+; absolute path
+;drivers_config_path = private
+
 ; This section is for declaring which driver to use for each institution.
 ; The key should be the Source ID of a specific institution, and the value
 ; should be the name of an ILS driver.

module/VuFind/src/VuFind/ILS/Driver/MultiBackend.php

@@ -65,6 +65,13 @@ class MultiBackend extends AbstractBase
      * @var string
      */
     protected $defaultDriver;
+    
+    /**
+     * The path to the driver configurations relative to the config path
+     * 
+     * @var string
+     */
+    protected $driversConfigPath;
 
     /**
      * The array of cached drivers
@@ -137,6 +144,10 @@ class MultiBackend extends AbstractBase
         $this->defaultDriver = isset($this->config['General']['default_driver'])
             ? $this->config['General']['default_driver']
             : null;
+        $this->driversConfigPath
+            = isset($this->config['General']['drivers_config_path'])
+            ? $this->config['General']['drivers_config_path']
+            : null;
     }
 
     /**
@@ -1354,7 +1365,11 @@ class MultiBackend extends AbstractBase
     {
         // Determine config file name based on class name:
         try {
-            $config = $this->configLoader->get($source);
+            $path = empty($this->driversConfigPath)
+                ? $source
+                : $this->driversConfigPath . '/' . $source;
+
+            $config = $this->configLoader->get($path);
         } catch (\Zend\Config\Exception\RuntimeException $e) {
             // Configuration loading failed; probably means file does not
             // exist -- just return an empty array in that case: