Run in the htdocs folder: npm install
to get files we need from JS libraries.

In the same way that composer install will pull in our customisations for PHP,
npm install will pull in our customisations for JavaScript.

Post install script
- patch-package to manage customisations
- new /patches folder for managing npm patches

Change-Id: Ic174d28870480564fccbe7b04d70c9de7a2547c5
Signed-off-by: Doris Tam <doristam@catalyst.net.nz>