Move more Core functions to ProbeCore

[mkeeter]

vid_pid, step, and write_reg are only available on ProbeCore. This PR removes them from the Core trait, adjusting signatures where necessary to force the concrete type.

[mkeeter]

I had to do a bit of extra wrangling to get the probeless build working; it now skips subcommands which are probe-only, both in the Cargo.toml (optional dependencies) and in codegen (ugly hacks).

[hawkw]

turbo-nit: should this maybe be an expect so that, if the build fails, we get an error message that actually tells us what happened?

[hawkw]

style nit, take it or leave it: i find throwing all of this in one giant tuple a little hard to follow; what do you think about doing something more like this:

Suggested change

	(
	// These are everything that can potentially pull in libusb
	["probe-rs", "humility-probes-core", "rusb"]
	.into_iter()
	.collect(),
	// We also look at which commands are enabled by the `probes`
	// feature on the `humility-bin` crate, then remove them.
	metadata
	.workspace_members
	.iter()
	.find(|p| metadata[p].name == "humility-bin")
	.map(|p| metadata[p].clone())
	.unwrap()
	.features["probes"]
	.iter()
	.flat_map(|p| {
	p.strip_prefix("cmd-")
	.map(|p| format!("humility-cmd-{p}"))
	})
	.collect::<BTreeSet<_>>(),
	)
	// These are everything that can potentially pull in libusb
	let banned_deps = ["probe-rs", "humility-probes-core", "rusb"]
	.into_iter()
	.collect();
	// We also look at which commands are enabled by the `probes`
	// feature on the `humility-bin` crate, then remove them.
	let disabled_cmds = metadata
	.workspace_members
	.iter()
	.find(|p| metadata[p].name == "humility-bin")
	.map(|p| metadata[p].clone())
	.unwrap()
	.features["probes"]
	.iter()
	.flat_map(|p| {
	p.strip_prefix("cmd-")
	.map(|p| format!("humility-cmd-{p}"))
	})
	.collect::<BTreeSet<_>>();
	(banned_deps, disabled_cmds)

this is a little more repetitive but i feel like it makes it slightly more obvious which expression corresponds to which variable?

[labbott]

I had to do a bit of extra wrangling to get the probeless build working; it now skips subcommands which are probe-only, both in the Cargo.toml (optional dependencies) and in codegen (ugly hacks).

I had hoped to be able to drop this after the probe-rs update but so long as we need to keep CMSIS DAP v1 around we will still need these hacks :(