[Feature] Upload support for specified slot (other than the selected slot) #2753

Is your feature request related to a problem? Please describe.
While programmatically uploading compiled code to the hub the protocol supports upload to the selected slot only.
It would be awesome to add program support for uploading to any other slots.

Describe the solution you'd like
I would assume protocol extension.
Later on an extension to the pybricks-code as well.

Parameters:
     * offset: The offset from the user RAM base address (32-bit little-endian unsigned integer).
     * payload: The data to write (0 to 507 bytes).
     * slot: The selected slot (255 for selected slot)

https://github.com/pybricks/pybricks-micropython/blob/5428d0d6742a17b682c4235e16298bafd600b514/lib/pbio/include/pbio/protocol.h#L146

Describe alternatives you've considered
No current alternatives are available.

Additional context
afarago/blocklypy-vscode#19