proxmox: create a common base (#1331) (#1378)

* proxmox: create a common base

Add a doc_fragment to share the documentation regarding authentication
parameters (api_host, api_user, api_password, api_token_id,
api_token_secret as well as the lone validate_certs).

Add a module_utils to hold common code such as the argument spec (again
related to authentication paramters), a helper function to convert from
Proxmox boolean representation to python and the base class
ProxmoxAnsible.
For now it only handles the connection to Proxmox VE API but more can be
added in the future.

To check if everything is well in place add three new modules:
proxmox_{domain,group,user}_info.

And finaly tests these new modules.

* Apply suggestions from code review

Co-authored-by: Felix Fontein <felix@fontein.de>

* Add tests/integration/targets/proxmox/aliases

Co-authored-by: Felix Fontein <felix@fontein.de>
(cherry picked from commit 51a08ea398)

Co-authored-by: Tristan Le Guern <tleguern@bouledef.eu>

plugins/doc_fragments/proxmox.py

@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+
+# 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):
+    # Common parameters for Proxmox VE modules
+    DOCUMENTATION = r'''
+options:
+  api_host:
+    description:
+      - Specify the target host of the Proxmox VE cluster.
+    type: str
+    required: true
+  api_user:
+    description:
+      - Specify the user to authenticate with.
+    type: str
+    required: true
+  api_password:
+    description:
+      - Specify the password to authenticate with.
+      - You can use C(PROXMOX_PASSWORD) environment variable.
+    type: str
+  api_token_id:
+    description:
+      - Specify the token ID.
+    type: str
+    version_added: 1.3.0
+  api_token_secret:
+    description:
+      - Specify the token secret.
+    type: str
+    version_added: 1.3.0
+  validate_certs:
+    description:
+      - If C(no), SSL certificates will not be validated.
+      - This should only be used on personally controlled sites using self-signed certificates.
+    type: bool
+    default: no
+requirements: [ "proxmoxer", "requests" ]
+'''