[orchagent] Add FEC frame loss ratio monitoring with predictive analytics (sonic-net#3869)

Implement observed and predicted FEC frame loss ratio calculations, using real-time metrics and linear regression on codeword error distribution for comprehensive network link health monitoring.

The predictive algorithm analyzes FEC codeword error patterns across symbol error bins, applies regression analysis to model error distribution trends, and extrapolates potential frame loss using IEEE FEC specifications. This enables early detection of degrading links before complete failure, supporting proactive network maintenance.

Feature HLD : port_fec_flr.md

Author: apoorv-arista

orchagent/Makefile.am

@@ -29,6 +29,7 @@ dist_swss_DATA = \
 		 pfc_restore.lua \
 		 pfc_restore_cisco-8000.lua \
 		 port_rates.lua \
+		 port_flr.lua \
 		 drop_monitor.lua \
 		 watermark_queue.lua \
 		 watermark_pg.lua \