website: add a script to automatically replace the list of available schemas.

This script, `list-blueprint-schemas`, is a blunt and fragile object, but it can get the work done.  Every time
it is run, it will get a list of all version tags from Git, compare them to all the available schemas available
by version, and print out a copy of `./website/docs/customize/blueprints/v1/structure.md` where it has replaced
the existing `Available Older Blueprint Schemas` collapse block with the most up-to-date version.

I will have to talk to @beryju and @tanberry to find out what they want done with this; would it be fine to just
run this at build time *before* the site is compiled, replacing the structure.md file with this dynamic block,
or can we generate it separately and [include it as a markdown
extension](https://stackoverflow.com/questions/65741307/how-to-include-import-markdown-file-content-in-docusaurus-v2)?

website/scripts/list-blueprint-schemas.mjs

@@ -0,0 +1,59 @@
+import { execSync } from "child_process";
+import { fileURLToPath } from "url";
+import { readFileSync } from "fs";
+import path from "path";
+
+const __dirname = fileURLToPath(new URL(".", import.meta.url));
+const structureFilePath = path.join(__dirname, "../docs/customize/blueprints/v1/structure.md");
+
+const cmd = ["git", "ls-remote", "--tags", "origin"].join(" ");
+const tagblob = execSync(cmd, { encoding: "utf8" });
+const itsadate = /\d{4}\.\d{1,2}\.\d{1,2}$/;
+const sortfn = (d1, d2) => {
+    const [y1, m1, y2, m2] = [d1[0], d1[1], d2[0], d2[1]].map((s) => parseInt(s, 10));
+    return y1 < y2 ? 1 : y1 > y2 ? -1 : m1 < m2 ? 1 : m1 > m2 ? -1 : 0;
+};
+
+const taglines = tagblob
+    .split("\n")
+    .filter((line) => itsadate.test(line))
+    .map((line) =>
+        line
+            .split("\t")[1]
+            .replace("refs/tags/version/", "")
+            .replace(/\.\d{1,2}$/, "")
+            .split("."),
+    )
+    .toSorted(sortfn)
+    .map(([a, b]) => `${a}-${b}`)
+    .reduce((acc, a) => (acc.includes(a) ? acc : [...acc, a]), []);
+
+const results = await Promise.allSettled(
+    taglines.map((version) =>
+        fetch(`https://version-${version}.goauthentik.io/blueprints/schema.json`, {
+            method: "HEAD",
+        }),
+    ),
+);
+
+const version = /version-(\d{4}-\d{1,2})/;
+
+const valid = results
+    .filter((result) => result.status === "fulfilled" && result.value.status === 200)
+    .map((result) => result.value.url)
+    .map((url) => {
+        const thedate = version.exec(url)[1];
+        return `- [Version ${thedate}](${url})`;
+    });
+
+const structurefile = readFileSync(structureFilePath, "utf-8");
+const schemablock = /<Collapse title="Available Older Blueprint Schemas">.*?<\/Collapse>/m;
+
+console.log(
+    structurefile.replace(
+        schemablock,
+        `<Collapse title="Available Older Blueprint Schemas">
+${valid.join("\n")}
+</Collapse>`,
+    ),
+);