Support external (i.e. user-defined) trace annotations (#195)

* Support external (i.e. user-defined) trace annotations

- tweaked the python examples to be more balanced
- updated the user-api example to conform to user API changes
- moved the get/set for State and ThreadState to state.{hpp,cpp}
- introduced user-provided trace annotations
- added perfetto python category
- moved coverage impl files around
- created enumerations for mapping category enums to category types
- created enumerations for mapping annotation type enums to annotation values
- moved tracing::add_perfetto_annotations to tracing/annotation.hpp
- utility make_index_sequence_range
- libomnitrace-dl: omnitrace_push_category_region
- libomnitrace-dl: omnitrace_pop_category_region
- libomnitrace-user: omnitrace_user_push_annotated_region
- libomnitrace-user: omnitrace_user_pop_annotated_region
- libpyomnitrace: support extra annotations via annotate_trace config value
  - filename
  - line
  - last attempted instr in bytecode (lasti)
  - argcount
  - num local variables
  - stacksize
- omnitrace-python: -a / --annotate-traces option

* tweak ubuntu-focal workflow

* Fix installation of omnitrace-user headers

* ubuntu-focal-codecov workflow update

- Install texinfo

* Update timemory submodule

source/lib/omnitrace/api.cpp

@@ -66,6 +66,40 @@ omnitrace_pop_region(const char* _name)
     return 0;
 }
 
+extern "C" int
+omnitrace_push_category_region(omnitrace_category_t _category, const char* _name,
+                               omnitrace_annotation_t* _annotations,
+                               size_t                  _annotation_count)
+{
+    try
+    {
+        omnitrace_push_category_region_hidden(_category, _name, _annotations,
+                                              _annotation_count);
+    } catch(std::exception& _e)
+    {
+        OMNITRACE_VERBOSE_F(1, "Exception caught: %s\n", _e.what());
+        return -1;
+    }
+    return 0;
+}
+
+extern "C" int
+omnitrace_pop_category_region(omnitrace_category_t _category, const char* _name,
+                              omnitrace_annotation_t* _annotations,
+                              size_t                  _annotation_count)
+{
+    try
+    {
+        omnitrace_pop_category_region_hidden(_category, _name, _annotations,
+                                             _annotation_count);
+    } catch(std::exception& _e)
+    {
+        OMNITRACE_VERBOSE_F(1, "Exception caught: %s\n", _e.what());
+        return -1;
+    }
+    return 0;
+}
+
 extern "C" void
 omnitrace_init_library(void)
 {