Create custom form themes for Dachcoms Formbuilder Plugin in Pimcore

From time to time you want to overwrite the default templates for forms in pimcore.
I had some problems to find the information I need as they are spreaded widley.

To get it to work it should look like this:

Filestructure

# src/AppBundle/Resources/config/pimcore/config.yml
form_builder:
    form:
        templates:
            ivoclar_div_layout:
                value: 'my_form_div_layout.html.twig'
                label: 'Custom form layout'
                default: true

{# tempaltes/bundles/FormBuilderBundle/Form/Theme/Macro/my_form_div_layout.html.twig #}
{% macro form_builder_form_head() %}
{% endmacro %}

{% macro form_builder_form_foot() %}
{% endmacro %}

{% macro form_builder_form_message(flash_messages) %}
    {% if flash_messages is not empty %}
        {% for label, messages in flash_messages %}
            {% for message in messages %}
                <div class="message message-{{ label }}">
                    {{ message|raw }}
                </div>
            {% endfor %}
        {% endfor %}
    {% endif %}
{% endmacro %}

{# tempaltes/bundles/FormBuilderBundle/Form/Theme/my_form_div_layout.html.twig #}
{% extends "form_div_layout.html.twig" %}

{%- block widget_attributes -%}
    id="{{ id }}" name="{{ name }}"
    {%- if disabled %} disabled="disabled"{% endif -%}
    {%- if required %} required="required"{% endif -%}
    {{ block('attributes') }}
{%- endblock widget_attributes -%}