feat: add unsafe (unencrypted) private key import / export functionality

[zivkovicmilos]

Description

Based on discussions with the Onbloc team, this PR introduces unsafe (unencrypted) private key export and import functionality to gnokey.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist (for contributors)

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

Manual tests

• Manually tested the import / export commands with the --unsafe flag.
• Added unit tests that cover this functionality.

Additional comments

cc @r3v4-onbloc

[r3v4s]

Hello @zivkovicmilos, currently adena supports private key import functionality if key is unarmored and formatted in hex.

Thanks to this pr, I think unsafe=true flag does satisfy unarmored

However we(adena) still need hex format, so can you add unarmored-hex flag too??

[zivkovicmilos]

Hey @r3v4s,

The import command with the unsafe flag expects unencrypted armor, and the export command with the unsafe flag exports unencrypted armor. Can't you do the hexing client side?

[r3v4s]

Hey @zivkovicmilos Adena needs raw byte value to handle hex encoding, which means user need to upload file(or idk.. somehow pass raw value), i.e user can't just copy & paste result from gnokey export -unsafe=true <- I think this isn't really good process for UX

[zivkovicmilos]

Got it - just to understand, you would like to hex the private key armor as well? (not just the raw private key bytes)

[r3v4s]

@zivkovicmilos nah unarmored hex is enough :D

[zivkovicmilos]

@r3v4s
Understood, so you just need the raw private key data, makes sense given the API we use around (even gnokey unarmors / armors when working with private key data).

I'll look into opening up a PR this week and tagging you to make sure we got the API right