Add simple integration test for openssl_certificate (#29038)

* openssl_certificate: Fix parameter assertion in Python3

Parameter assertion in Python3 is broken. pyOpenSSL get_X() functions
returns b'' type string and tries to compare it with '' string, leading
to failure.

The error mentionned above has been fixed by sanitizing the inputs from
a user to the assert only backend.

Also, this error was hidden by the fact that the improper check method
was called in the generate() functions.

* Add simple integration test for openssl_certificate

* remove subject == issuer assertion

* run integration tests only on supported hosts

* change min supported version to 0.15.x

* Add test for more CSR fields

* also convert dict members to bytes

* fix version_compare

* openssl_{csr, certificate}: Fail if pyOpenSSL <= 0.15

Previous 0.13 pyOpenSSL was a C-binding, and required the parameter
passed to add_extention to be in ASN.1. This has changed with the move
to 0.14 and it is now all pythong and string based.

Previous the 0.15 release, the `get_extensions()` method didn't exist,
since the modules rely heavily on it we ensure pyOpenSSL version is at
last 0.15.0.

* check pyopenssl version in openssl_csr integration test

test/integration/targets/openssl_csr/tasks/main.yml

@@ -1,11 +1,14 @@
-- name: Generate privatekey
-  openssl_privatekey:
-    path: '{{ output_dir }}/privatekey.pem'
+- block:
+    - name: Generate privatekey
+      openssl_privatekey:
+        path: '{{ output_dir }}/privatekey.pem'
 
-- name: Generate CSR
-  openssl_csr:
-    path: '{{ output_dir }}/csr.csr'
-    privatekey_path: '{{ output_dir }}/privatekey.pem'
-    commonName: 'www.ansible.com'
+    - name: Generate CSR
+      openssl_csr:
+        path: '{{ output_dir }}/csr.csr'
+        privatekey_path: '{{ output_dir }}/privatekey.pem'
+        commonName: 'www.ansible.com'
 
-- import_tasks: ../tests/validate.yml
+    - import_tasks: ../tests/validate.yml
+
+  when: pyopenssl_version.stdout|version_compare('0.15', '>=')