De-duplicate tx hashes and pub keys to save memory (off by default) (#382)

P2Pool-main: 8.2 MB saved
P2Pool-mini: 66 MB saved
P2Pool-nano: 25.2 MB saved

The feature is available only when building from source and is intended for use on low-memory systems (for example, a VPS server with < 1 GB RAM).

It only makes sense to use with `--no-cache --no-randomx` in the command line because cache and RandomX hasher take much more memory.

src/console_commands.cpp

@@ -224,6 +224,10 @@ static void do_status(p2pool *m_pool, const char * /* args */)
 
 	m_pool->print_merge_mining_status();
 
+#ifdef WITH_INDEXED_HASHES
+	indexed_hash::print_status();
+#endif
+
 	bkg_jobs_tracker->print_status();
 
 	if (p2p) {