Support a unique interface to the logger crate

[ia0]

Currently the format for defmt and log and different. It would be much more convenient to have a unique syntax for a common (and restricted) subset of those, typically to print common types like integers, strings, and bytes.

The idea would be to change the logger crate to be a proc-macro crate, and do the format conversion logic at compile-time. The goal is that such logic:

wasefire/crates/protocol-usb/src/device.rs

Lines 91 to 94 in ac32ec7

	#[cfg(not(feature = "defmt"))]
	Some(result) => log::debug!("Reading {:02x?}", result),
	#[cfg(feature = "defmt")]
	Some(result) => log::debug!("Reading {=[u8]:02x}", result),

would be a single line:

Some(result) => log::debug!("Reading {:02x?}", result),

See knurling-rs/defmt#149 for a similar issue in the defmt repository.