[WebAPI] Removal of various device sensor event features

[chrisdavidmills]

Acceptance criteria

1. • The listed features are documented sufficiently on MDN
2. • BCD is updated
3. • Interactive example and data repos are updated if appropriate
4. • The content has been reviewed as needed

Features to document

1. Remove DeviceProximityEvent
2. Remove UserProximityEvent
3. Remove ondeviceproximity/onuserproximity
4. Disable ondevicelight

Related Gecko bugs

1. • Remove DeviceProximityEvent. A bit of cleanup work required here. DeviceProximityEvent and UserProximityEvent have both been removed from other browsers for a while, so BCD needs updating for Firefox (also window.ondeviceproximity and window.onuserproximity). Also, consider whether it would make sense to keep the pages, or just delete them all.
2. • Disable ondevicelight attribute behind the flag. Need to update ondevicelight to show it disabled, add experimental features entry perhaps.

For folks helping with Firefox-related documentation features — make sure above AC have been done, but also:

• Set bugs to dev-doc-complete
• Add entry to Firefox release notes if feature is enabled in release
• Add entry to Firefox experimental features page if feature is not yet enabled in release

[hamishwillee]

• BCD for DeviceProximityEvent - in review
• BCD for UserProximityEvent - in review
• BCD for DeviceLightEvent - in review
• DeviceProximityEvent docs - vastly cut back docs in FF89: DeviceProximityEvent deprecation and removal.  #4472 and added severe removal warnings.
• Further docs for proximity and light events updates
• Release note

Note that some of these events still available under KaiOS, but that is IMO "niche" and therefore not mentioned.

[hamishwillee]

@chrisdavidmills This is all done and merged now except for removing dev-doc complete in https://bugzilla.mozilla.org/show_bug.cgi?id=1699707 and https://bugzilla.mozilla.org/show_bug.cgi?id=1701824#c6

[Note the BCD stuff only went in a few days ago, so not yet reflected in compatibility table flaws]

[chrisdavidmills]

Agreed, set to DDC, and closing!