* Removed the ./sources/static/js folder and content
* Removed the `<script>` tags (loading the Javascript) from the ./sources/index.html file

HgO authored Nov 23, 2019 and Ilja committed Nov 23, 2019

Adding backup and restore
Extra changes in the install script to use $app instead of 'neutrinet'

- update the `upgrade` script
- add instruction about how to upgrade in the README
- update the index.html file so it doesn't contain information that
might change often (link to our website instead)

What this upgrade does:
- renew the certificate
- add a daily cron job that will check if the certificate must be
  renewed

The `renew_from_cube` script only renew the cert if it will [expire in
less than 4
months](https://github.com/Neutrinet/renew_cert/blob/master/renew_from_cube.py#L29).