ci: test gcp demo site build (#805)

* ci: test docs-publish

* Require unit tests for dry run

* ci: Make sure our docs publish is executable

* Try to correct path issue

* Try repo prefix

* Try as yarn command

* Need a workspace to attach to from previous step

* Add before we call our bash script

* See if we can enforce commands being available -- or just install locally?

* Try again

* Try SSH

* Include username in gh https url

* Note regarding failure on PR branches

* Remove docs publish from PR workflow

* chore: ability to specify an alternative html-template at build time

* chore: add command to build demo PWA website output

* chore: remove unused CI code

* Testing GCP capabilities

* syntax

* Naming

* naming

platform/viewer/public/html-templates/index.html

@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta
+      name="viewport"
+      content="width=device-width, initial-scale=1, shrink-to-fit=no"
+    />
+    <meta name="theme-color" content="#000000" />
+
+    <link rel="manifest" href="<%= PUBLIC_URL %>/manifest.json" />
+    <script
+      type="text/javascript"
+      src="<%= PUBLIC_URL %>/<%= APP_CONFIG %>"
+    ></script>
+
+    <title>OHIF Viewer</title>
+
+    <!-- WEB FONTS -->
+    <link
+      href="https://fonts.googleapis.com/css?family=Roboto:100,300,400,500,700|Sanchez&display=swap"
+      rel="stylesheet"
+    />
+
+    <!-- EXTENSIONS -->
+    <!-- <script type="text/javascript" src="path/to/some-extension.js"></script>
+
+    <script>
+      window.config.extensions = [SomeExtension];
+    </script> -->
+  </head>
+
+  <body>
+    <noscript> You need to enable JavaScript to run this app. </noscript>
+
+    <div id="root"></div>
+  </body>
+</html>