build(aio): move gulp tasks to package.json

Generate the docs with `yarn docs`.
Test the doc generation code with `yarn docs-test`

The docs are automatically built as part of the `yarn build` task,
so there is no need to rebuild them in the test_aio.sh file

scripts/ci/test-aio.sh

@@ -17,12 +17,6 @@ source ${thisDir}/_travis-fold.sh
     yarn run lint
   travisFoldEnd "test.aio.lint"
 
-  # Generate docs files
-  # TODO(i): why is this in 'test' phase and not in the 'build' phase?
-  travisFoldStart "test.aio.doc-gen"
-    $(npm bin)/gulp docs
-  travisFoldEnd "test.aio.doc-gen"
-
 
   # Start xvfb for local Chrome used for testing
   if [[ ${TRAVIS} ]]; then

scripts/ci/test-docs.sh

@@ -10,6 +10,6 @@ source ${thisDir}/_travis-fold.sh
 travisFoldStart "test.docs"
   (
     cd ${PROJECT_ROOT}/aio
-    $(npm bin)/gulp docs-test
+    yarn docs-test
   )
 travisFoldEnd "test.docs"