Deploy static sites requiring npm build

Summary:
A bunch of sites use the ZURB WebApp template to generate static
sites from Foundation, handlebars templates and YAML data, with
a Gulp build chain to pack and minimize assets.

For each of them, a Jenkins job has been created to clone the
repository and prepare the npm build.

Deployment consists of two steps:

• create a directory with deploy account access
• run the Jenkins job to build and publish the site there

Fixes T1465.

Test Plan:

salt-call --local state.apply roles/webserver-content/org/nasqueron/daeghrefn
salt-call --local state.apply roles/webserver-content/org/nasqueron/docs
salt-call --local state.apply roles/webserver-content/org/nasqueron/infra
salt-call --local state.apply roles/webserver-content/org/nasqueron/rain

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1465

Differential Revision: https://devcentral.nasqueron.org/D1902