feat: Add form ui example

Test css grid system for form fields.

source/screens/demo/examples/ui/form.njk

@@ -0,0 +1,45 @@
+---
+title: Form
+tags: 
+  - demoExample
+  - ui
+---
+{% extends "demo/_app.njk" %}
+
+{% block title %}{{ title }}
+{% endblock %}
+
+{% block links %}
+	<link href="{{ pageBase }}css/ui.css" media="all" rel="stylesheet"/>
+{% endblock %}
+
+{% block head %}
+	{{ super() }}
+{% endblock %}
+
+{% block body %}
+	<div id="head">
+		<h1>Formulare</h1>
+		<button data-action="add">Hinzufügen</button>
+	</div>
+	<div id="grid">
+		<div>a</div>
+		<div>b</div>
+	</div>
+{% endblock %}
+
+{%- block script %}
+	{{ super() }}
+	<script>
+		const add = document.querySelector('[data-action=add]');
+
+		add.addEventListener('click', (e) => {
+				const grid = document.getElementById('grid');
+				const item = document.createElement('div');
+
+				item.style.backgroundColor = '#f0f';
+				item.textContent = 'c'
+				grid.appendChild(item);
+		});
+	</script>
+{% endblock %}