DN-8130: show md5 and sha1 in hunt result output

[sbneto]

TL;DR

• Text formatter: SHA1 and MD5 lines added under SHA256 for both live_result and historical_result. Only rendered when the field is present, so older API responses or URL artifacts (null md5/sha1) don't print bare `SHA1: None` rows.
• Hash formatters: `SHA1Output` and `MD5Output` gain `historical_result` / `live_result` methods (mirroring `SHA256Output`), so `--output-format sha1` / `md5` work uniformly across hunt results and artifact instances.
• JSON / PrettyJSON formatters: no code change needed — they emit `result.json` raw, so md5/sha1 surface automatically once polyswarm-api parses them.

Ticket: DN-8130.

Requires

• polyswarm-api PR polyswarm/polyswarm-api#292 — adds the `md5` / `sha1` attributes on `LiveHuntResult` and `HistoricalHuntResult`.
• artifact-index PR polyswarm/artifact-index#1865 — server-side change that surfaces the fields.

All three PRs are forward-compatible at each layer: against older artifact-index, md5/sha1 stay null and the CLI skips the lines.

Test plan

• `pytest tests/` passes locally (59/59 pass against existing cassettes)
• Against an artifact-index deployment carrying #1865 and polyswarm-api #292, `polyswarm live result ` and `polyswarm historical result ` show SHA1 / MD5 lines in text mode and the keys in JSON mode
• `polyswarm --output-format sha1 live result ` and `--output-format md5 live result ` print just the hash
• Older deployments without md5/sha1: the text output omits the lines, JSON output is unchanged shape