On very large node, LimitNOFILES=80000 may not enough size, it can cause "Too many files" error. To avoid that, let's increase LimitNOFILES on scylla_setup stage, generate optimal value calurated from memory size and number of cpus. Closes scylladb/scylla-enterprise#4304 Closes scylladb/scylladb#20443