refactor(rosetta): silence the rossetta stdout logs by default

[mur-me]

Issue

During the check of our logging for other issue, I've found that we have a log of rossetta logs that aren't bringing any value - just HTTP GET hits, e.g.:

Oct 06 10:53:19 some_server harmony-explorer-node[25121]: 2025-10-06 10:53:19 Rosetta: GET / 21.131µs
Oct 06 10:53:29 some_server harmony-explorer-node[25121]: 2025-10-06 10:53:29 Rosetta: GET / 29.978µs
Oct 06 10:53:39 some_server harmony-explorer-node[25121]: 2025-10-06 10:53:39 Rosetta: GET / 20.881µs
Oct 06 10:53:49 some_server harmony-explorer-node[25121]: 2025-10-06 10:53:49 Rosetta: GET / 34.486µs
Oct 06 10:53:59 some_server harmony-explorer-node[25121]: 2025-10-06 10:53:59 Rosetta: GET / 52.753µs
Oct 06 10:54:09 some_server harmony-explorer-node[25121]: 2025-10-06 10:54:09 Rosetta: GET / 20.52µs
Oct 06 10:54:19 some_server harmony-explorer-node[25121]: 2025-10-06 10:54:19 Rosetta: GET / 73.003µs
Oct 06 10:54:29 some_server harmony-explorer-node[25121]: 2025-10-06 10:54:29 Rosetta: GET / 24.238µs
Oct 06 10:54:39 some_server harmony-explorer-node[25121]: 2025-10-06 10:54:39 Rosetta: GET / 18.486µs

For one day this is 8956 entities for the RPC node in the testnet, you can imagine the hit rate in the mainnet:

$ journalctl -u harmony --since "1d ago" | grep 'Rosetta:' | wc -l
8956

So to deal with this issue, I've put debug level here + if we need it - we can easily enable it by setting log level.

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What was done:

• set debug level
• remove stdout completly for the rosetta http.Handler