Implement GetCapabilities RPC for tlbmc HftService.

Add GetCapabilities RPC support to HftServiceImpl in tlbmc, reporting supported ServiceFeatures.

Currently, tlbmc only supports on_change edge filtering and does not support SDT. Implement GetSupportedEdgeFilteringDetail() in edge_filter.h/cc to advertise on_change_supported and allow easy extension for future edge filter details. Implement GetCapabilities unary RPC handler in HftServiceImpl with client authorization checks.

Google-Bug-Id:533523581
PiperOrigin-RevId: 967306002
Change-Id: Iafe07d70e7c5f9f675ce2e272367a73e13290043