Bug 34793: Add default HTML Customisations for cookie information

Bug 34793: Add default HTML Customisations for cookie information

This patch adds some default html customisation content for the cookie
consent feature.

Test plan
1) Run through the installer and pick to import the sample news items
2) Confirm that after enabling the CookieConsent preference that the
   default content appears in the cookie bar at the bottom of the page
   and in the modal that appears after clicking 'More information'

Mentored-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>