Support importing private keys functionality

[sosthene-nitrokey]

Initially from @anotherbridge: Nitrokey#41

Type

Feature Request

Description

After running the generate command of pivy-tool worked well as expected and I was able to create a CSR as well as import a certificate that I got from the CSR I wanted to check whether it is also possible to import keys that have been previously created using the import functionality of pivy-tool and ran

cat | pivy-tool import 9A

The response I got was the following:

pivy-tool: error occurred while executing 'import'
Caused by cmd_import: failed to import key
in cmd_import() at pivy-tool.c:1492
Caused by NotSupportedError: Importing private keys not supported by PIV device 'Nitrokey Nitrokey 3'
in ykpiv_import() at piv.c:3345
Caused by APDUError: Card replied with SW=6a81 (FUNC_NOT_SUPPORTED) to INS_IMPORT_ASYM(9a)
in ykpiv_import() at piv.c:3345

Therefore I wanted to open this feature request for implementing this functionality.

Further Info

pivy Version: 0.11.2
Firmware version: v1.5.0-test.20231030