keyinfo: display information about private keys

Usage: keyinfo [-v] files...

The -v option will dump the D and N values of RSA private keys.

Example:

keyinfo ec_private.pem
[+] Type: EC
[+] Curve: P256

With -v:

$ keyinfo -v private.key
[+] Type: RSA
[+] Size: 2048
D: 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
E: 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