docs: point package metadata at official repo

[jtc268]

Summary

• Updates package.json and the lockfile root metadata from the retired fork / upstream package names to the official Bitgesell RPC client repository.
• Removes README setup references to the retired ruimarinho/bitgesell-core Docker image and the empty fork link.
• Aligns README setup copy with the current Bitgesell client defaults: BGLd, BGL.conf, mainnet port 8454, and testnet port 18332.
• Adds a small metadata regression test so stale fork and Docker references do not come back.

Evidence

• https://github.com/naftalimurgor/bitgesell-core returns 404.
• https://hub.docker.com/r/ruimarinho/bitgesell-core returns 404.
• The official active repo is BitgesellOfficial/js-bitgesellcore-rpc.
• src/index.js maps Bitgesell mainnet to port 8454 and testnet to 18332.
• Bitgesell Core docs use bin/BGLd and BGL.conf.
• Submitted under the Bitgesell improvement program: BGL (Bitgesell) Bounty/Improvement Program ($50000 budget) bitgesell#81.

Validation

• npm ci --ignore-scripts -> installed dependencies; lifecycle scripts intentionally skipped because this tarball checkout has no Docker Compose file.
• ./node_modules/.bin/mocha test/package_metadata_test.js --timeout 20000 --require should -> 2 passing
• npm test -- --grep 'Package metadata' -> 2 passing
• npm run lint -- --quiet -> passed
• Stale-link scan over README.md package.json package-lock.json -> no retired fork or Docker image references

[MyTH-zyxeon]

Maintainers: this looks like a reviewer-friendly #81 candidate.

What I verified from the diff:

• package.json / package-lock.json now point at the official BitgesellOfficial/js-bitgesellcore-rpc repository instead of the retired fork metadata.
• README setup/docs now align with current Bitgesell naming and defaults (BGL-cli, bin/BGLd, BGL.conf, mainnet RPC port 8454).
• test/package_metadata_test.js adds a useful regression guard so stale fork / Docker image references and lockfile-package metadata drift do not quietly come back.

For acceptance, the main things I would check are:

• the documented default ports still match src/index.js network mapping,
• the README multi-wallet example remains runnable with the non-Docker bin/BGLd form now shown,
• and the metadata test stays in the default npm test path so future package/README edits fail loudly if they reintroduce old links.

If those points match maintainer intent, this seems like a clean doc+metadata correctness improvement rather than formatting-only churn.