Update footer NOS banner + Move it to left column

• Links are not up to date
  replace:https://connect.nuxeo.com/nuxeo/site/connect/trial/form?source=unregisteredClientBanner&product=CAP%207.4-SNAPSHOT
  by: https://connect.nuxeo.com/register/#/
• The design could be more appealing
• The sentences to register are not very appealing too

"This Nuxeo instance is not registered to Nuxeo Online Services: you won't be able to get the most recent fixes and stay up to date.
(20 hotfix(es) published since this release.)
Nuxeo version: 7.4-SNAPSHOT. Register and enable Nuxeo Online Services to benefit from automatic maintenance."

=> we don't need to know that our instance is not registered, if it's not registered, I need to know why I need to register / what are my benefits to do so.

+ HF VERSION will be added with NXP-17942.