Move auto-generated core classes into public include/

This CL fixes a bunch of pending TODOs and removes
layering violations from the client library.
It mainly moves a bunch of auto-generated C++ classes
(and some of their deps) from include/ext to include/
so the Client API can depend on them.

Bug: 132678367
Change-Id: Ifd8a06dbeb114e2f4a600408d9ecd14623874373
diff --git a/src/tracing/core/test_config.cc b/src/tracing/core/test_config.cc
index ee5e7ac..02ba732 100644
--- a/src/tracing/core/test_config.cc
+++ b/src/tracing/core/test_config.cc
@@ -25,7 +25,7 @@
  * ./tools/gen_tracing_cpp_headers_from_protos
  */
 
-#include "perfetto/ext/tracing/core/test_config.h"
+#include "perfetto/tracing/core/test_config.h"
 
 #include "perfetto/config/test_config.pb.h"