investigate endpoint 1 requirement for boot keyboards

[tlyu]

Describe the bug

There are some reports that even in 2021, PC vendors have BIOSes that require IN 1 (and possibly OUT 1) endpoint(s) in order to recognize a Boot Keyboard. (There are also reports that it's required to be Interface 0, but the evidence seems less reliable on that.)

It's not clear whether OUT 1 is required. An interrupt out endpoint isn't required by either the HID specification in general or the Boot Keyboard specification. I haven't yet seen any evidence that any KVMs or BIOSes actually require a functioning OUT 1 endpoint for LED Output Reports, as opposed to using a Set Report control request.

To Reproduce

Details are unknown. We could experiment with forcing an endpoint of IN 1 for the Boot Keyboard to see if that helps any of the reported problems with KVM or BIOS compatibility. Note that forcing endpoint numbers is likely impossible on AVR without patching the Arduino core, which I'm guessing we've been avoiding.

Additional information

espressif/arduino-esp32#6964