Added missing middleware to trim input

app/Http/Middleware/TrimStrings.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace BookStack\Http\Middleware;
+
+use Illuminate\Foundation\Http\Middleware\TrimStrings as BaseTrimmer;
+
+class TrimStrings extends BaseTrimmer
+{
+    /**
+     * The names of the attributes that should not be trimmed.
+     *
+     * @var array
+     */
+    protected $except = [
+        'password',
+        'password_confirmation',
+    ];
+}