accessibility dictation: first round

[phillco]

No rush on reviewing this! I figured it would be good to get your thoughts on this first batch of changes, before I go on to push more stuff. I'm probably going to focus on cursorless-on-JetBrains for the rest of the weekend so I'm not blocked on this review.

In this change:

• using AX to acquire context for dictation formatters
• APIs for overriding in specific apps, a sample override for Messages.app
• the ability to automatically enable AX for Electron
• basic debugging of accessibility using hissing

My thought is the experimental branch can be a sort of middle ground between main and our feature branches. Ambitious beta testers could use it and it also gives us a place to merge our development changes together and test them together. We can promote it to main afterwards.

[phillco]

Thanks, made revisions

[phillco]

Done