[fingerprint] helpful for master keys

[shannona]

Now that we're exporting xprvs and xpubs with [fingerprint/derivation path], we should also export the master keys with [fingerprint] to give all the info that we can.

This matches the standard descriptor-based key methodology from Bitcoin Core, which includes:

• Optionally, key origin information, consisting of:
  • An open bracket [
  • Exactly 8 hex characters for the fingerprint of the key where the derivation starts (see BIP32 for details)
  • Followed by zero or more /NUM or /NUM' path elements to indicate unhardened or hardened derivation steps between the fingerprint and the key or xpub/xprv root that follows
  • A closing bracket ]

[ChristopherA]

I believe this is will be closed with 1.4 when you complete the information block.

@wolfmcnally, close this issue with that PR is merged.

[wolfmcnally]

Master Key IDs are now displayed in all Seed Object Information Blocks.

[shannona]

Master fingerprint definitely in the OIB.