Use gulp to build the pages

[laurentS]

Instead of manually updating the HTML pages, we should complete the setup initiated by Raphaelle when she rebuilt the site.

In short, it could look like this:

• edit the "source files" (all the xxxx.shtml) locally
• run gulp build to generate the actual HTML files under a subfolder ( say docs)
• push the result to github, which would then deploy the site from this subfolder

The structure for this is already in the source-code branch, but we've diverged a little with the commits from 2019-10-10 in master.

To fix this:

• setup npm on your laptop (it's installed with node.js, for OSX, get the installer from https://nodejs.org/en/download/ (use the "LTS" version)
• in a terminal, you should be able to run npm -v and see something like 12.16.2
• from there, go to the folder where you've cloned this git repo, and run npm install to install all the dependencies required to build the pages (the dependencies are installed in a folder called node_modules)
• once completed, you should be able to run gulp develop in the same folder. It will start a small local webserver, and show you the url (something like http://localhost:8000) to open to see the local version of the site (if its not working, try node_modules/.bin/gulp develop)
• change any of the .Shtml files, save, and the local site will rebuild itself automatically
• when you're happy with the changes, run gulp build, commit your changes to the .shtml and docs/*.html files (do not commit the node_modules folder), and push to github (and open a PR)

Once that workflow is working ok, I would suggest "backporting" the changes made in master to the source-code branch, pushing everything, and create a PR to make that workflow the normal one. We'll need to modify how github deploys the site at this point, but we can figure this out later.

[jhenshall]

Done and migrated to new 'website' repo.