Bump version to 3.0.0-dev0, remove deprecated functionality and implement announced breaking changes (#873)

* Bump verison to 3.0.0-dev0.

* Change check mode behavior for *_pipe modules.

* Remove PyOpenSSL backend.

* Remove PyOpenSSL setup.

* Change default of asn1_base64.

* Remove deprecated common module utils.

* Remove get_default_argspec().

* Mark two methods as abstract.

* Remove ACME v1 support.

* Remove retrieve_acme_v1_certificate().

* Remove deprecated docs fragment.

* Change meaning of mode parameter.

* Mark no longer used option as 'to deprecate'.

plugins/modules/openssl_csr_pipe.py

@@ -29,10 +29,7 @@ attributes:
   check_mode:
     support: full
     details:
-      - Currently in check mode, private keys will not be (re-)generated, only the changed status is set. This will change
-        in community.crypto 3.0.0.
-      - From community.crypto 3.0.0 on, the module will ignore check mode and always behave as if check mode is not active.
-        If you think this breaks your use-case of this module, please create an issue in the community.crypto repository.
+      - Since community.crypto 3.0.0, the module ignores check mode and always behaves as if check mode is not active.
 options:
   content:
     description:
@@ -157,18 +154,7 @@ class CertificateSigningRequestModule(object):
     def generate(self, module):
         """Generate the certificate signing request."""
         if self.module_backend.needs_regeneration():
-            if not self.check_mode:
-                self.module_backend.generate_csr()
-            else:
-                self.module.deprecate(
-                    "Check mode support for openssl_csr_pipe will change in community.crypto 3.0.0"
-                    " to behave the same as without check mode. You can get that behavior right now"
-                    " by adding `check_mode: false` to the openssl_csr_pipe task. If you think this"
-                    " breaks your use-case of this module, please create an issue in the"
-                    " community.crypto repository",
-                    version="3.0.0",
-                    collection_name="community.crypto",
-                )
+            self.module_backend.generate_csr()
             self.changed = True
 
     def dump(self):