Improve automation doc

The automation documentation is now branded and styled:

• html5 update
• brand the app with logo / header / links / footer
• style default elements of doc.
  ==> Done.

==> Still to do:
Still to do through subtasks:

• use webengine to be able to add web resources easily (css, img, js)
• make menu foldable / collapse / provide nicer navigation (now we have a lot of operations / chains)
• provide better display of JSON definitions

See:
nuxeo-automation-server/src/main/resources/org/nuxeo/ecm/automation/server/jaxrs/doc/index.ftl
doc URL: /nuxeo/site/automation/doc/
https://intranet.nuxeo.com/nuxeo/site/automation/doc/