Purge old neutron manifests and move our customized files

outside from community neutron manifest.

This makes it easier to carry rebases forward and prevent conflicts.
This may be squased into the merge from upstream commit.

blueprint: ml2-neutron

Fuel-CI: disable
Change-Id: I9b69c2ab4cb4e476083ec9516f442d9b1911b2a7
Merge "Purge old neutron manifests and move our customized files"