read_repair_decision: fix operator<<(std::ostream&, ...)
read_repair_decision: fix operator<<(std::ostream&, ...)

Argument-dependent lookup requires that the operator be declared in the
same namespace as the class; move it there.

While at it, de-static it, it only causes bloat.

scylladb/scylla,duarten/scylla,duarten/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla