[workers] Start migrating workers to the monorepo

infra/workers/.gitignore

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+node_modules/
+.DS_Store
+.wrangler/
+
+# Workers mostly have dev dependencies, and usually only wrangler, so exact
+# version details and the resulting `yarn.lock` is unnecessary noise.
+#
+# If we need to pin some runtime dependency, we can pin it to an exact version
+# in the package.json itself.
+yarn.lock

infra/workers/.prettierrc.json

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+{
+    "tabWidth": 4
+}

infra/workers/README.md

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+# Cloudflare Workers
+
+Source code for our [Cloudflare
+Workers](https://developers.cloudflare.com/workers/).
+
+Each worker is a self contained directory with its each `package.json`.
+
+## Deploying
+
+* Switch to a worker directory, e.g. `cd health-check`.
+
+* Install dependencies (if needed) with `yarn`
+
+* Login into wrangler (if needed) using `yarn wrangler login`
+
+* Deploy! `yarn wrangler publish`
+
+Wrangler is the CLI provided by Cloudflare to manage workers. Apart from
+deploying, it also allows us to stream logs from running workers by using `yarn
+wrangler tail`.
+
+## Creating a new worker
+
+Copy paste an existing one. Unironically this is a good option because the
+Cloudflare template has a lot of unnecessary noise, but if really do want to
+create one from scratch, use `npm create cloudflare@latest`.
+
+To import an existing worker from the Cloudflare dashboard, use
+
+```sh
+npm create cloudflare@2 existing-worker-name -- --type pre-existing --existing-script existing-worker-name
+```

infra/workers/tsconfig.base.json

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+{
+    /* A shared TSConfig for use by TypeScript Cloudflare Workers */
+    /* TSConfig docs: https://aka.ms/tsconfig.json */
+    "compilerOptions": {
+        /* tsc is used for by us for type checking, not compilation (the
+           Cloudflare workers runtime natively supports TypeScript) */
+        "noEmit": true,
+
+        /* The Workers runtime supports the latest and greatest */
+        /* https://developers.cloudflare.com/workers/reference/languages/#javascript--typescript */
+        "lib": ["esnext"],
+        "target": "esnext",
+        "module": "esnext",
+
+        /* Types that are implicitly available */
+        /* https://www.npmjs.com/package/@cloudflare/workers-types */
+        "types": ["@cloudflare/workers-types"],
+
+        /* Tell TypeScript how to lookup the file for a given import */
+        "moduleResolution": "node",
+
+        /* Speed things up by not type checking `node_modules` */
+        "skipLibCheck": true,
+        /* Require the `type` modifier when importing types */
+        "verbatimModuleSyntax": true,
+        /* Enable importing .json files */
+        "resolveJsonModule": true,
+
+        /* strict and then some */
+        "strict": true,
+        "noImplicitReturns": true,
+        "noUnusedParameters": true,
+        "noUnusedLocals": true,
+        "noFallthroughCasesInSwitch": true,
+        "noUncheckedIndexedAccess": true,
+        "exactOptionalPropertyTypes": true
+    }
+}