Refresh bglutil README for Bitgesell

[manuelsampedro1]

Summary

• refresh the README title, package description, badges, and install command for Bitgesell's bglutil module
• remove stale btcsuite/Conformal release-verification instructions that do not apply to this fork
• add a short local development section with the current go test ./... command

Validation

• checked the README for stale btcsuite/btcutil, Package btcutil, Conformal, and old GoDoc references with rg
• git diff --check
• Go tests were not run locally because the Go toolchain is not installed in this environment

[MyTH-zyxeon]

Maintainer review note for the btcsuite#81 improvement queue:

I checked head 2727e531: this is a narrow README fork-alignment patch, and the two easy-to-break references line up. .github/workflows/go.yml exists for the new build badge, and go.mod declares module github.com/bitgesellofficial/bglutil, matching the new Go Reference badge and go get command.

Acceptance checks:

• Run go test ./... in a Go-enabled maintainer environment, since the PR author could not run it locally.
• Render the README once to confirm the workflow badge, pkg.go.dev badge, and install command are clickable and not case-drifted.
• Keep the stale-upstream check for btcutil, btcsuite, Conformal, and old GoDoc wording clean after merge.
• Confirm removing the Conformal GPG verification section is intended until Bitgesell has a fork-specific release-signing policy to document.

No wallet/key/node/live-chain scope; this is docs/package hygiene only.