This adds support for Ed25519 keys from files in PEM format when using
OpenSSL with Ed25519 support. The default encoding for the PEM file is
expected to be PKCS#8. Encrypted files are supported.
For the lack of an API, it is not possible to export keys in PEM format,
only in OpenSSH format.
Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>