Refactor POST handling.

- Split into admin and user handlers, each admin page gets its own file now
- Enforce role access once for admin POST requests
- Automatically load POST logic for admin-based requests based on the referring page, otherwise automatically load all user request logic
- Add support for using custom POST handlers

post/admin/admin_settings_telemetry.php

@@ -0,0 +1,18 @@
+<?php
+
+if (isset($_POST['edit_telemetry_settings'])) {
+
+    validateCSRFToken($_POST['csrf_token']);
+
+    $config_telemetry = intval($_POST['config_telemetry']);
+
+    mysqli_query($mysqli,"UPDATE settings SET config_telemetry = $config_telemetry WHERE company_id = 1");
+
+    // Logging
+    mysqli_query($mysqli,"INSERT INTO logs SET log_type = 'Settings', log_action = 'Modify', log_description = '$session_name modified telemetry settings', log_ip = '$session_ip', log_user_agent = '$session_user_agent', log_user_id = $session_user_id");
+
+    $_SESSION['alert_message'] = "Telemetry Settings updated";
+
+    header("Location: " . $_SERVER["HTTP_REFERER"]);
+
+}