Add Time Machine extension to community catalog (#2580)

* Add Time Machine extension to community catalog

Add time-machine extension submitted by @teeyo to:
- extensions/catalog.community.json (alphabetical order)
- docs/community/extensions.md community extensions table

Closes #2568

* Fix alphabetical ordering of time-machine entry

Move time-machine before tinyspec in both catalog JSON (by ID)
and docs table (by name), since time < tiny alphabetically.