Prevented normal users from changing own email

To address #1542

Updates to only allow email changes by users with the users-manage role
permission.

resources/views/form/text.blade.php

@@ -1,6 +1,7 @@
 <input type="text" id="{{ $name }}" name="{{ $name }}"
        @if($errors->has($name)) class="text-neg" @endif
        @if(isset($placeholder)) placeholder="{{$placeholder}}" @endif
+       @if(isset($disabled) && $disabled) disabled="disabled" @endif
        @if(isset($tabindex)) tabindex="{{$tabindex}}" @endif
        @if(isset($model) || old($name)) value="{{ old($name) ? old($name) : $model->$name}}" @endif>
 @if($errors->has($name))