Add workflow to generate doxygen on tag push (#6189)

* Add workflow to generate doxygen on tag push.

Took 17 minutes

* Publish correct dir.

Took 3 minutes

* Don't include common/libs.

Took 20 minutes

* Update workflow

Took 1 hour 25 minutes

* Style Doxygen output.

Took 55 minutes

---------

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

doxygen_style.css

@@ -0,0 +1,45 @@
+/* === Accent Tuning for Doxygen Dark Mode === */
+
+/* Main accent color */
+:root {
+    --main-accent: #33a946;
+}
+
+/* Links */
+a, a:visited {
+    color: var(--main-accent) !important;
+}
+
+a:hover {
+    color: #4fd467 !important; /* lighter green */
+}
+
+/* Project title */
+#projectname {
+    color: var(--main-accent) !important;
+}
+
+/* Current sidebar item */
+#side-nav .selected {
+    border-left: 3px solid var(--main-accent) !important;
+}
+
+/* Tabs */
+.tablist li.current {
+    background: var(--main-accent) !important;
+    color: #fff !important;
+}
+
+/* Search box focus */
+#MSearchField:focus {
+    outline: 1px solid var(--main-accent) !important;
+}
+
+/* Code block border highlight */
+pre, code {
+    border: 1px solid #333;
+}
+
+pre.fragment {
+    border-color: var(--main-accent) !important;
+}