loader: replaceQdisc/Datapath - perform bpffs map migrations using Go
loader: replaceQdisc/Datapath - perform bpffs map migrations using Go

This uses the newly-ported Go logic to execute bpffs map migrations in
replaceQdisc and replaceDatapath.

Also simplified the control flow a bit to avoid accidentally shadowing err.
The revert behaviour has been made more explicit.

Signed-off-by: Timo Beckers <98c2d5a1e48c998bd9ba9dbc53d6857beae1c9bd@isovalent.com>

tklauser/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium