Cross-repo collection of all filters in the ecosystem

[mariajgrimaldi]

Description

Some comments I've gathered from the community survey on the challenges/suggestions section:

I wish it was easier to see the named release when each event/filter was added. It would also be helpful to know which Open edX services an event or filter is used in (edx-platform, credentials, etc.).

Finding a comprehensive list of events/filters (especially those outside of edx-platform) is challenging, and they are not all well documented. I added autodoc support for events, but there is probably more work to be done there.
More clarity about which events are event-bus capable and the differences between bus and non-bus events would also be great.

A cross-repo collection of all events / filters in the ecosystem. It would be great to have a consistent way to access permissions inside a filter. This has been a point of confusion in the instructor dashboard filter around where permissions are / should be checked.