Fill in many of the gaps in the tc netlink spec, including stats attrs,
classes and actions. Many documentation strings have also been added.

This is still a work in progress, albeit fairly complete:
 - there are still many attributes left as binary blobs.
 - actions have not had much testing
Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240129223458.52046-14-donald.hunter@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>