Candidate Yang models for openstack neutron in OpenDaylight Controller

Candidate Yang models for openstack neutron in OpenDaylight Controller

This patch is moving the neutron models pushed to controller repo through following gerrit
https://git.opendaylight.org/gerrit/#/c/13970/1

Scope of this patch is to define yang models in OpenDaylight controller for openstack neutron
APIs, so that we can enable the mechanism to store the neutron resource data in md-sal data
store for other applications to consume.
Patch 2: Address comments from reviewer
Patch 3: Removed whitespaces
Patch 4: Split models into 4 files. Fixed all reviewer comments(except one).
Patch 5: Fixed a build error(removed neutron.yang)
Patch 6: Fixed one remaining reviewer comment(move network-type to identity)
Patch 7: Fixed many comments(including tabs, moving provider to separate file, naming issues, re-org etc.
Patch 8: Added neutron-L3.yang module and fixed some more review comments
Patch 9: Fixed more comments from Ryan. Added augments in provider and L3 module.
Patch 10: Added neutron-metering.yang
Patch 11: Added neutron-secgroups.yang
Patch 12: Fixed uuid issue with Ed's patch + moved network defns into networks module
Patch 13: Fixed Ryan's latest comments(remove trailing space & Fix description)
Patch 14: Fixed Ryan's comments about Security group rules
Change-Id: I1fbc79e6e9856fa7cd18dd92d138e2b84a6d6a3c
Signed-off-by: Anil Vishnoi <vishnoianil@gmail.com>
Signed-off-by: Kiran Sreenivasa <kkoushik@brocade.com>