Add openssl_privatekey_convert module (#362)

* Add openssl_privatekey_convert module.

* Extend tests and fix bugs.

* Fix wrong required.

* Fix condition.

* Fix bad tests.

* Fix documentation for format.

* Fix copyright lines.

plugins/doc_fragments/module_privatekey_convert.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+
+# Copyright: (c) 2022, Felix Fontein <felix@fontein.de>
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+
+class ModuleDocFragment(object):
+
+    # Standard files documentation fragment
+    DOCUMENTATION = r'''
+requirements:
+    - cryptography >= 1.2.3 (older versions might work as well)
+options:
+    src_path:
+        description:
+            - Name of the file containing the OpenSSL private key to convert.
+            - Exactly one of I(src_path) or I(src_content) must be specified.
+        type: path
+    src_content:
+        description:
+            - The content of the file containing the OpenSSL private key to convert.
+            - Exactly one of I(src_path) or I(src_content) must be specified.
+        type: str
+    src_passphrase:
+        description:
+            - The passphrase for the private key to load.
+        type: str
+    dest_passphrase:
+        description:
+            - The passphrase for the private key to store.
+        type: str
+    format:
+        description:
+            - Determines which format the destination private key should be written in.
+            - Please note that not every key can be exported in any format, and that not every
+              format supports encryption.
+        type: str
+        choices: [ pkcs1, pkcs8, raw ]
+        required: true
+seealso:
+    - module: community.crypto.openssl_privatekey
+    - module: community.crypto.openssl_privatekey_pipe
+    - module: community.crypto.openssl_publickey
+'''