refactor(route/caniuse): merge respec-caniuse-route to main

[sidvishnoi]

1. Brings https://github.com/sidvishnoi/respec-caniuse-route into this repo. I've chosen routes/caniuse/lib as the destination.

- import { createResponseBody } from "respec-caniuse-route";
+ import { createResponseBody } from "./lib/index.js";

2. Added a sh utility, which respec-caniuse-route/scraper and others can use consistently. I've used this it in spec-prod, so it's "well tested".

- const args = shouldClone
-   ? ['clone', 'https://github.com/Fyrd/caniuse.git', 'caniuse-raw']
-   : ['pull', 'origin', 'master'];
- const cwd = shouldClone ? path.resolve(DATA_DIR) : dataDir;

- return new Promise<boolean>((resolve, reject) => {
-   const git = spawn('git', args, { cwd });
-   let hasUpdated = true;
-   git.stdout.on('data', (data: ArrayBuffer) => {
-     hasUpdated = !data.toString().includes('Already up to date');
-   });
-   git.on('error', reject);
-   git.on('exit', (code: number) => {
-     if (code !== 0) {
-       reject(new Error(`The process exited with code ${code}`));
-     } else {
-       resolve(hasUpdated);
-     }
-   });
- });
+ const stdout = await sh(command, { cwd, output: "stream" });
+ const hasUpdated = !stdout.toString().includes("Already up to date");
+ return hasUpdated;

3. routes/caniuse/lib/index.ts makes use of ucontent instead of manipulating template strings. i.e.

-  return `<button class="${className}" title="${title}">${text}</button>`;
+  return html`<button class="${className}" title="${title}">${text}</button>`;

4. routes/caniuse/lib/scraper.ts does shallow git clone/pull to save space on server (from 125MB to 25MB). i.e.

- ['clone', 'https://github.com/Fyrd/caniuse.git', 'caniuse-raw']
+ `git clone ${INPUT_REPO_SRC} ${INPUT_REPO_NAME} --filter=blob:none`

5. routes/caniuse/lib/index.ts uses utils/mem-cache instead of its own cache.
6. No changes for end user.

[marcoscaceres]

looks good