* import rsa and ecdsa public keys
* allow import_version to update public keys - wip
* allow import_version to update public keys
* move check key fields into func
* put private/public keys in same switch cases
* fix method in UpdateKeyVersion
* move asymmetrics keys switch to its own method - WIP
* test import public and update it with private counterpart
* test import public keys
* use public_key to encrypt if RSAKey is not present and failed to decrypt
if key version does not have a private key
* move key to KeyEntry parsing from Policy to KeyEntry method
* move extracting of key from input fields into helper function
* change back policy Import signature to keep backwards compatibility and
add new method to import private or public keys
* test import with imported public rsa and ecdsa keys
* descriptions and error messages
* error messages, remove comments and unused code
* changelog
* documentation - wip
* suggested changes - error messages/typos and unwrap public key passed
* fix unwrap key error
* fail if both key fields have been set
* fix in extractKeyFromFields, passing a PolicyRequest wouldn't not work
* checks for read, sign and verify endpoints so they don't return errors when a private key was not imported and tests
* handle panic on "export key" endpoint if imported key is public
* fmt
* remove 'isPrivateKey' argument from 'UpdateKeyVersion' and
'parseFromKey' methods
also: rename 'UpdateKeyVersion' method to 'ImportPrivateKeyForVersion' and 'IsPublicKeyImported' to 'IsPrivateKeyMissing'
* delete 'RSAPublicKey' when private key is imported
* path_export: return public_key for ecdsa and rsa when there's no private key imported
* allow signed data validation with pss algorithm
* remove NOTE comment
* fix typo in EC public key export where empty derBytes was being used
* export rsa public key in pkcs8 format instead of pkcs1 and improve test
* change logic on how check for is private key missing is calculated
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Co-authored-by: Alexander Scheel <alex.scheel@hashicorp.com>