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/python/omnitrace/__main__.py

@@ -220,6 +220,16 @@ def parse_args(args=None):
         default=_profiler_config.trace_c,
         help="Enable profiling C functions",
     )
+    parser.add_argument(
+        "-a",
+        "--annotate-trace",
+        type=str2bool,
+        nargs="?",
+        metavar="BOOL",
+        const=True,
+        default=_profiler_config.annotate_trace,
+        help="Enable perfetto debug annotations",
+    )
 
     return parser.parse_args(args)
 
@@ -322,6 +332,7 @@ def main():
     _profiler_config.exclude_modules = opts.module_exclude
     _profiler_config.restrict_functions = opts.function_restrict
     _profiler_config.restrict_modules = opts.module_restrict
+    _profiler_config.annotate_trace = opts.annotate_trace
     _profiler_config.verbosity = opts.verbosity
 
     print("[omnitrace]> profiling: {}".format(argv))