FRR (MetalLB) support for BFD strict-mode

1. Proposed title of this feature request

FRR (MetalLB) support for BFD strict-mode

2. What is the nature and description of the request?

 
MetalLB, which uses FRR, does support BFD, but not strict-mode. When the strict-mode is set up in the router,in the router side the bgp session is not started because it requires BFD (because of strict-mode), while FRR doesn't instantiate the BFD session if the BGP one is not established.

3. Why does the customer need this? (List the business requirements here)

The customer wants this functionality within MetalLB to ensure the BGP links are closed when there is no network connection with the OpenShift cluster and the BGP peer. They want to achieve fast link failure detection and network re-convergence. 

4. List any affected packages or components.

MetalLB