[web/navigation] use add_onload instead of inline javascript href This way our javascript code isn't thrown out by the html cleaner e.g. when using the rql rest directive and a table view. To make things simpler, we now always use ajax URLs for navigation, even when we would previously have used regular links. Closes #3501626

usr/lib/PY_VERSION/*-packages/cubicweb/web
usr/share/cubicweb/cubes/shared/data
usr/share/cubicweb/cubes/shared/wdoc