Bug fixes

Fixes two issues:
2936867 - Notice: Only variables should be passed by reference
2981234 - Wrong usage of renderRoot

Fixed hmac key validation on webhooks. In order to do this we are now storing the shared secret from the ContentHub service.

Changes since 7.x-1.0-beta9:

Fixing an issue #2991250 (Images are loaded via HTTP when the site is loaded via HTTPS), adding the image fluid setting

Updated the json data so it can be safely processed on Surveillant.

This release adds a new feature:
- When the filter is in the URL, it is set for the rest of the session. Before it was set for only the duration of the request.