[Extension Bindings] Use returns_async to define all async returns

This CL completes the rework of how asynchronous returns are represented
in extension API schemas and the model the JSON schema compiler
generates from them. Now all asynchronous returns are represented with
the 'returns_asyc' field and default to supporting promise based calls
unless the 'does_not_support_promises' field is specified.

The IDL schema processing has also been updated to reflect this, with
one exception case being added with a new extended attribute for the two
automation APIs which have a trailing function parameter which is a
function that gets called more than once.

Along with all these changes, the remaining JSON schemas have been
updated to define their async returns using the 'returns_async' field,
with any remaining non-promise supporting functions being marked as
such with a description and link to a tracking bug for that case where
appropriate.

Bug: 978538, 1288583
Change-Id: I042bb70e7dd171b1aa1d88ea85b27ef4b87e9ef3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5121609
Reviewed-by: Ovidio Ruiz-Henríquez <odejesush@chromium.org>
Commit-Queue: Tim <tjudkins@chromium.org>
Reviewed-by: Devlin Cronin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1256320}