Handle OMNITRACE_ENABLED + minor updates (#78)

- handle OMNITRACE_ENABLED=OFF by disabling everything
- use set_data to get wrappee in pthread_create_gotcha
- clear roctracer_data storage if roctracer not initialized

[ROCm/rocprofiler-systems commit: f82845388a]

projects/rocprofiler-systems/source/lib/omnitrace/library/ompt.cpp

@@ -61,6 +61,7 @@ bool _init_toolset_off = (trait::runtime_enabled<ompt_toolset_t>::set(false),
 void
 setup()
 {
+    if(!tim::settings::enabled()) return;
     trait::runtime_enabled<ompt_toolset_t>::set(true);
     trait::runtime_enabled<ompt_context_t>::set(true);
     comp::user_ompt_bundle::global_init();