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/library/runtime.hpp

@@ -107,23 +107,6 @@ get_cpu_cid_entry(uint64_t _cid, int64_t _tid = threading::get_id()) TIMEMORY_HO
 tim::mutex_t&
 get_cpu_cid_stack_lock(int64_t _tid = threading::get_id()) TIMEMORY_HOT;
 
-ThreadState&
-get_thread_state() TIMEMORY_HOT;
-
-/// returns old state
-ThreadState set_thread_state(ThreadState) TIMEMORY_HOT;
-
-ThreadState push_thread_state(ThreadState) TIMEMORY_HOT;
-
-ThreadState
-pop_thread_state() TIMEMORY_HOT;
-
-struct scoped_thread_state
-{
-    scoped_thread_state(ThreadState _v) { push_thread_state(_v); }
-    ~scoped_thread_state() { pop_thread_state(); }
-};
-
 // query current value
 bool
 sampling_enabled_on_child_threads();
@@ -147,12 +130,6 @@ struct scoped_child_sampling
 };
 }  // namespace omnitrace
 
-#define OMNITRACE_SCOPED_THREAD_STATE(STATE)                                             \
-    ::omnitrace::scoped_thread_state OMNITRACE_VARIABLE(_scoped_thread_state_, __LINE__) \
-    {                                                                                    \
-        ::omnitrace::STATE                                                               \
-    }
-
 #define OMNITRACE_SCOPED_SAMPLING_ON_CHILD_THREADS(VALUE)                                \
     ::omnitrace::scoped_child_sampling OMNITRACE_VARIABLE(_scoped_child_sampling_,       \
                                                           __LINE__)                      \