Move sml and selfcontain to library repositories

cmd/hepto/config.go

cmd/hepto/root.go

go.mod

go.sum

pkg/cluster/cluster.go

pkg/cluster/services.go

pkg/selfcontain/config.go

pkg/selfcontain/container.go

pkg/selfcontain/defaults.go

pkg/selfcontain/init.go

pkg/selfcontain/net.go

pkg/selfcontain/utils.go

pkg/sml/delegate.go

pkg/sml/instrumentation.go

pkg/sml/memberlist.go

pkg/sml/node.go

pkg/sml/transport.go