API docs script should relativize internal links

[Eric-Arellano]

If API docs use https://docs.quantum.ibm.com/start/configure-qiskit-local, then we should change this to /start/configure-qiskit-local. That is, we should chop off the prefix.

We actually already did this for qiskit.org:

documentation/scripts/lib/api/Pkg.ts

Lines 386 to 404 in bbccec5

	function transformLink(link: Link): Link | undefined {
	const updateText = link.url === link.text;
	const prefixes = [
	"https://qiskit.org/documentation/apidoc/",
	"https://qiskit.org/documentation/stubs/",
	];
	const prefix = prefixes.find((prefix) => link.url.startsWith(prefix));
	if (!prefix) {
	return;
	}
	let [url, anchor] = link.url.split("#");
	url = removePrefix(url, prefix);
	url = removeSuffix(url, ".html");
	if (anchor && anchor !== url) {
	url = `${url}#${anchor}`;
	}
	const newText = updateText ? url : undefined;
	return { url: `/api/qiskit/${url}`, text: newText };
	}

We need to keep that code for historical API docs. But we should expand it to handle https://docs.quantum.ibm.com and https://docs.quantum-computing.ibm.com. We should also apply the logic to Qiskit, whereas right now it only is used for Runtime and Provider.