feat: Implement floors, locations, and racks management

- Added list, edit, and save functionalities for floors, locations, and racks.
- Enhanced UI with search and filter options for better usability.
- Implemented SVG upload for floor plans in the floors module.
- Added validation for required fields in the save processes.
- Improved navigation in the header to reflect new modules.
- Styled forms and tables for a consistent look and feel across modules.

app/modules/locations/save.php

@@ -0,0 +1,44 @@
+<?php
+/**
+ * app/modules/locations/save.php
+ */
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    header('Location: ?module=locations&action=list');
+    exit;
+}
+
+$locationId = (int)($_POST['id'] ?? 0);
+$name = trim($_POST['name'] ?? '');
+$comment = trim($_POST['comment'] ?? '');
+
+$errors = [];
+
+if (empty($name)) {
+    $errors[] = "Name ist erforderlich";
+}
+
+if (!empty($errors)) {
+    $_SESSION['error'] = implode(', ', $errors);
+    $redirectUrl = $locationId ? "?module=locations&action=edit&id=$locationId" : "?module=locations&action=edit";
+    header("Location: $redirectUrl");
+    exit;
+}
+
+if ($locationId > 0) {
+    $sql->set(
+        "UPDATE locations SET name = ?, comment = ? WHERE id = ?",
+        "ssi",
+        [$name, $comment, $locationId]
+    );
+} else {
+    $sql->set(
+        "INSERT INTO locations (name, comment) VALUES (?, ?)",
+        "ss",
+        [$name, $comment]
+    );
+}
+
+$_SESSION['success'] = "Standort gespeichert";
+header('Location: ?module=locations&action=list');
+exit;