chore: Move to Typescript (#2783)

This PR moves the entire project to Typescript. Due to the ~1000 ignores this will lead to a messy codebase for a while, but the churn is worth it – all of those ignore comments are places that were never type-safe previously.

closes #1282

server/tracing.ts

@@ -0,0 +1,12 @@
+// If the DataDog agent is installed and the DD_API_KEY environment variable is
+// in the environment then we can safely attempt to start the DD tracer
+if (process.env.DD_API_KEY) {
+  // eslint-disable-next-line @typescript-eslint/no-var-requires
+  require("dd-trace").init({
+    // SOURCE_COMMIT is used by Docker Hub
+    // SOURCE_VERSION is used by Heroku
+    version: process.env.SOURCE_COMMIT || process.env.SOURCE_VERSION,
+  });
+}
+
+export {};