CLOUDFLAREAPI: Adds CF_WORKER_ROUTE (#1243)

* CLOUDFLAREAPI: Adds CF_WORKER_ROUTE.

- CLOUDFLAREAPI: Initial support for CF_WORKER_ROUTE.
- Put CF_WORKER_ROUTE behind a per-domain feature-flag.
- Adds Integration Test.
- Create Cloudflare workers for tests.
- Updates documentation.

* Workaround for updateWorkerRoute causing stack overflow.

* Sets AccountID.

* Updates to latest master (Thanks @tresni!).

* Removes $CLOUDFLAREAPI_ACCOUNTNAME.

* Add alltrue() filter and -cfworkers flag

* Final workers changes

* alltrue() should be implemented like other filters.
* Update documentation.

Co-authored-by: Tom Limoncelli <tlimoncelli@stackoverflow.com>

pkg/js/parse_tests/040-cfWorkerRoute.js

@@ -0,0 +1,3 @@
+D("foo.com","none",
+    CF_WORKER_ROUTE("test.foo.com","test-worker")
+);