docs: refresh UTXO dump setup commands

[Luzijano]

Summary

• removes the duplicated wget in the Bitgesell node setup command
• updates the Go install command from the old contributor fork path to the official BitgesellOfficial/bitgesell-utxo-dump repository
• trims a trailing space in the adjacent dpkg command

Validation

• RED/proof before fix: README assertion failed because setup contained wget wget ... and go install github.com/naftalimurgor/bgl-utxo-dump@latest
• GREEN/proof after fix: README assertion passes with the official install path and no duplicated wget
• git diff --check

AI/tooling disclosure: prepared with Hermes Agent automation.

[MyTH-zyxeon]

Maintainer-facing review assist for the Bitgesell #81 improvement-program queue:

I rechecked this PR at head a3afdf3c04f0bb07ec95dbe236a0c5398c56b369. It is a one-file README cleanup, currently OPEN/MERGEABLE/CLEAN, with no prior PR comments or reviews.

Suggested acceptance checks before merge:

• keep the duplicated wget wget fix; that is a direct copy/paste blocker for a new user following the setup instructions;
• confirm the go install github.com/BitgesellOfficial/bitgesell-utxo-dump@latest module path is valid for the official repository/module metadata, not only the GitHub URL;
• decide whether the pinned bitgesell_0.1.9_amd64.deb release is still the intended setup target, since this PR improves the command but leaves the old package version unchanged;
• consider whether the perl-modules-5.30 Ubuntu ports URL is still appropriate for the documented target platform, or should be called out as version/platform-specific in a follow-up;
• classify this under #81 as contributor-onboarding/docs hygiene rather than a runtime or chain-behavior payout.

No code or consensus behavior changes are introduced by this PR; the main merge gate is whether the official Go module path and old release/package references are still the canonical setup path.