feat: add docsearch

Author: atymic

config.production.php

@@ -4,7 +4,7 @@
     'baseUrl' => 'https://geocoder-php.org',
     'production' => true,
 
-    // DocSearch credentials
-    'docsearchApiKey' => '',
-    'docsearchIndexName' => '',
+    // Algolia DocSearch credentials
+    'docsearchApiKey' => '4b4f0156a1bce73ed44722c1d4f3187a',
+    'docsearchIndexName' => 'geocoder-php',
 ];