Add support for client-specific API keys

Refactoring API. Added a contact update endpoint.
Small misc changes.

api/v1/update_output.php

@@ -0,0 +1,23 @@
+<?php
+/*
+ * API - update_output.php
+ * Included on calls to update.php endpoints
+ * Checks the status of the update SQL query ($update_sql)
+ * Returns success data / fail messages
+ */
+
+// Check if the insert query was successful
+if(isset($update_id) && is_numeric($update_id) && $update_id > 0){
+  // Insert successful
+  $return_arr['success'] = "True";
+  $return_arr['count'] = $update_id;
+}
+
+// Query returned false: something went wrong, or it was declined due to required variables missing
+else{
+  $return_arr['success'] = "False";
+  $return_arr['message'] = "Auth success but update query failed/returned no results. Ensure ALL required variables are provided and database schema is up-to-date. Most likely cause: non-existent module (contact/ticket/etc) id";
+}
+
+echo json_encode($return_arr);
+exit();