Add a Doxyfile and preliminary module-level docs.

src/tlscontext.js.h

@@ -1,5 +1,11 @@
 #pragma once
 
+/**
+** \defgroup tls_js TLS Interface
+** Exposes \ref tls to JS.
+** @{
+*/
+
 #include "quickjs.h"
 
 typedef struct _tf_tls_context_t tf_tls_context_t;
@@ -7,3 +13,5 @@ typedef struct _tf_tls_context_t tf_tls_context_t;
 JSValue tf_tls_context_register(JSContext* context);
 tf_tls_context_t* tf_tls_context_get(JSValue value);
 int tf_tls_context_get_count();
+
+/** @} */