Get rid of more wildcard imports and add boilerplate to more modules

This commit cleans up the following module categories:
* messaging
* inventory
* crypto
* commands
* clustering
* cloud/webfaction
* cloud/docker
* cloud/digital_ocean

lib/ansible/modules/crypto/openssl_privatekey.py

@@ -2,19 +2,11 @@
 # -*- coding: utf-8 -*-
 
 # (c) 2016, Yanis Guenane <yanis+ansible@guenane.org>
-#
-# Ansible is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Ansible is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+# 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
+
 
 ANSIBLE_METADATA = {'metadata_version': '1.0',
                     'status': ['preview'],
@@ -134,11 +126,6 @@ fingerprint:
 
 import os
 
-from ansible.module_utils import crypto as crypto_utils
-from ansible.module_utils._text import to_native
-from ansible.module_utils.basic import AnsibleModule
-from ansible.module_utils.pycompat24 import get_exception
-
 try:
     from OpenSSL import crypto
 except ImportError:
@@ -146,6 +133,10 @@ except ImportError:
 else:
     pyopenssl_found = True
 
+from ansible.module_utils import crypto as crypto_utils
+from ansible.module_utils._text import to_native
+from ansible.module_utils.basic import AnsibleModule
+
 
 class PrivateKeyError(crypto_utils.OpenSSLObjectError):
     pass