Add PhantomJS to CircleCI config or document

[byrond]

Just want to capture this somewhere, because it came up on another project.

Projects often need to have tests where JavaScript is required during testing. This requires the use of PhantomJS, but it isn't started by default and has been moved to the browsers-legacy Docker image variant on CircleCI. This usually requires the following change:

diff --git a/.circleci/config.yml b/.circleci/config.yml
index bb1e491d..02576053 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -3,7 +3,7 @@ jobs:
   build:
     working_directory: ~/akamai
     docker:
-      - image: circleci/php:7.1-node-browsers
+      - image: circleci/php:7.1-node-browsers-legacy
       - image: tkuchiki/delayed-mysql
         environment:
           MYSQL_ALLOW_EMPTY_PASSWORD: yes
@@ -77,6 +77,10 @@ jobs:
           # Dockerize is preinstalled in circleci/* docker image
           command: dockerize -wait tcp://127.0.0.1:3306 -timeout 120s
 
+      - run:
+          name: Start PhantomJS
+          command: phantomjs --webdriver=8643
+          background: true
       - run:
           name: Build Drupal's settings.php
           command: vendor/bin/phing build

We should either add this to the standard config in the skeleton (if it is required often enough), or we should document how to enable PhantomJS for projects that need it.

[damontgomery]

For the Federated Search Demo, I put in a PR to set up Chrome Headless. I haven't tried that for Circle CI, but I think that's the recommendation since PhantomJS is no longer under active development.

palantirnet/the-vagrant#62