add c-at-e app which serves the documentation website

Author: Jake Champion

.gitignore

@@ -15,3 +15,5 @@ node_modules/
 /js-compute-runtime.wasm
 tests/wpt-harness/wpt-test-runner.js
 wpt-runtime.wasm
+docs-app/bin/main.wasm
+docs-app/pkg/javascript-docs.tar.gz