Add corporate design.

_templates/breadcrumbs.html

@@ -0,0 +1,40 @@
+{%- extends "sphinx_rtd_theme/breadcrumbs.html" %}
+
+{% block breadcrumbs %}
+<li>
+	<div style="font-size: 105%;font-weight: 600;">
+		Godot Engine Contributions Documentation
+	</div>
+	<ul class="wy-breadcrumbs">
+		{{ super() }}
+	</ul>
+</li>
+{% endblock %}
+
+{% block breadcrumbs_aside %}
+{% if not meta or meta.get('github_url') != 'hide' %}
+<li style="float: right; text-align: right;">
+	<ul>
+		{{ super() }}
+	</ul>
+
+	<style>
+		.godot-edit-guidelines {
+			font-size: 14px;
+			float: right;
+			clear: both;
+			padding-top: 4px;
+		}
+
+		@media screen and (max-width: 480px) {
+			.godot-edit-guidelines {
+				display: none;
+			}
+		}
+	</style>
+	<a class="godot-edit-guidelines" href="https://docs.godotengine.org/en/">
+		Visit the engine documentation!
+	</a>
+</li>
+{% endif %}
+{% endblock %}