Resurrecting the second bullet from #1334

• Figure out how to fix favicon / logo more generally (here's a start https://github.com/tock/tock/tree/doc-updates)

display_bsod internally calls the map_framebuffer syscall to map the framebuffer, because we . were lazy and didn't want to duplicate code. However this syscall retrieves the current process to map it in its process memory.

When we're panicking during early boot, CURRENT_PROCESS is None and this panics in the panic handler.

We should instead do a second function that maps it in the k

Improve diagnostics by converting the error to IncompatibleValueConversion(AmlType, AmlType). Convert all places where the error is emitted to fill in the correct types (these will be able to be hardcoded for most conversions).

NOTE: This relies on the merging of #47 to introduce the AmlType type