Add support for restart to bootloader via USB command

[stdvar]

Description

This change will piggyback on existing HID descriptor used by shared EP for extra key and shared keyboard/mouse.
New feature report section in the HID descriptor is added to allow PC to send HID feature report to KB and thus instruct it to restart in bootloader.
Added code to distinguish between input/output/feature reports.
set_report buffer that used to handle led status is increased from (1+1 size) to (1+8 size).
This should work for any keyboard since handler uses generic bootloader_jump() function.

There is new USB_FEATURE_ENABLE option that enables shared ep just like EXTRAKEY_ENABLE. So only one option is needed but new option added for consistency in case user opted out of using EXTRAKEY or other shared ep options.

Report to send to KB is struct.pack("<II", 0x5AA555AA, 0xCC3300FF).

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[tzarc]

Jumping to bootloader without external intervention is a security risk and will not be accepted, I'm afraid.

The in-progress XAP development will require functionality like bootloader jump to be guarded by an unlock key combination before becoming accessible. See here for more details: https://hackmd.io/@tzarc/ryY5liviO

[zvecr]

Jumping to bootloader without external intervention is a security risk and will not be accepted, I'm afraid.

#7456 was removed for exactly this reason. For now I think it would be best to defer items in this area till XAP has progressed.

[tzarc]

As was #11892.

[stdvar]

how different having raw_hid from having hid feature report configured? either way KB is open to accept packets. or the concern is bootloader jump itself?

[tzarc]

The bootloader jump itself is an attack vector.

[stale]

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