Bump master to Neon in per-project docs/conf.yaml

Each project's master branch docs/conf.yaml file should specify version Neon. This dictates the ODL version in the main header for a project's docs. All of them I've checked except NetConf are still Fluorine (which should only be stable/fluorine).

Projects may want to update other docs to Neon before or alongside updating this header to Neon. Or projects might prefer to go ahead and update this to make it obvious when something in the docs that references a version other than Neon needs to be updated. For now just send patches that bump this version. 

Should also add this to the release process somehow.

Reported and discussion here: https://lists.opendaylight.org/pipermail/documentation/2018-October/001502.html