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##### SUMMARY
Allow to specify a new "format" parameter in "openssl_privatekey". Today the output format is decided by a very simple heuristic which requires further commands to work properly.
I need, for example, to generate a RSA private key but in PKCS8 format. The current heuristic uses OpenSSH format for RSA keys and only uses PKCS8 for Ed25519 and similar. This makes me use a "command" with "openssl" to convert the generated key, which leads to idempotency problems and unnecessary complexity.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
openssl_privatekey

##### ADDITIONAL INFORMATION
<!--- Describe how the feature would be used, why it is needed and what it would solve -->
The current heuristic should be kept unless overwritten by user.

<!--- Paste example playbooks or commands between quotes below -->
```yaml
openssl_privatekey:
  path: /etc/ssl/private/ansible.com.pem
  format: pkcs8
```
The values allowed are `pkcs1`, `raw` and `pkcs8`

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if bytesstr is None:
        return bytesstr
    data = binascii.hexlify(bytesstr)
    data = to_text(b':'.join(data[i:i + 2] for i in range(0, len(data), 2)))
    return data
def cryptography_decode_name(name):
    '''
    Given a cryptography x509.Name object, returns a string.
    Raises an OpenSSLObjectError if the name is not supported.
    '''
    if isinstance(name, x509.DNSName):
        return 'DNS:{0}'.format(name.value)
    if isinstance(name, x509.IPAddress):
        return 'IP:{0}'.format(name.value.compressed)
    if isinstance(name, x509.RFC822Name):
        return 'email:{0}'.format(name.value)
    if isinstance(name, x509.UniformResourceIdentifier):
        return 'URI:{0}'.format(name.value)
    if isinstance(name, x509.DirectoryName):
        
        return 'DirName:' + ''.join(['/{0}:{1}'.format(attribute.oid._name, attribute.value) for attribute in name.value])
    if isinstance(name, x509.RegisteredID):
        
        return 'RegisteredID:{0}'.format(name.value)
    if isinstance(name, x509.OtherName):
        
        return '{0}:{1}'.format(name.type_id.dotted_string, _get_hex(name.value))
    raise OpenSSLObjectError('Cannot decode name "{0}"'.format(name))
def _cryptography_get_keyusage(usage):