Improving Autofocus documentation

[ianhi]

I'm trying to better understand using autofocus in MM and in doing so have run into a few pain points in the docs.

1. There is no centralized list of autofocus related pages.
   • Having something likehttps://micro-manager.org/autofocus/<pagename> and .org/autofocus give the table of contents would be helpful
2. https://micro-manager.org/Autofocus_manual should not link to simple autofocus without mentioning that it's deprecated.
3. Searching for autofocus through the website search bar gives non-existant pages. E.g. searching on the website I found this: https://micro-manager.org/Autofocus_Device_Adapter
4. https://micro-manager.org/Autofocus_setup is very confusing. I'm not really sure why I should save that .bsh file and what it would do
5. Most crucially for me: there is no mention of how to interact with hardware autofocus. Even some of the explanation given by @nicost here(https://forum.image.sc/t/what-does-autofocusdrive-do-how-to-use-autofocus-in-mda/59257) would be awesome to include.

While autofocus is mentioned in the user guide it is a pretty brief description (could be a good place to link out to other places) and uses some terminology I don't full understand. It writes:

If you have an autofocus device, it can be configured to activate at each timepoint. If you set “Skip Frames” to a value greater than 1, then it will activate 1 in every N frames (e.g. setting it to 3 means using autofocus 1 in every 3 frames).

But I'm not actually sure what a frame is. A definition would be handy here.

[marktsuchida]

Related: micro-manager/mmCoreAndDevices#156