As discussed during the Zed PTG (see [1]) , due to changed product
development priorities we expect the BFD related extensions not
to get implemented. This patch reverts all relevant changes.
Revert Exception for BFD: BfdMonitorInUse,
a3b564dabf
Revert BFD validator, d126257982
Revert Fix hostroute validation with BFD,
5ff14c63c8
Revert extension for adding bfd monitors to extraroutes,
eb2c8a3c97
Revert BFD api def, f8c5b72cc8
[1]: https://etherpad.opendev.org/p/neutron-zed-ptg#L111
Related-Bug: #1907089
Change-Id: Ia532e4aa6ba2ed9e5ba4db75a250293890d9019d