Add api_facts module (#88)

* Add API docs fragment.

* Improve documentation.

* Move API code to api module_utils.

* Improve docs.

* Add api_facts module.

Does not yet support 'config'. I'm not sure whether that's actually
possible with the API.

* Convert subnet to integer if possible.

* Cleanup.

* Linting and fix tests.

* Remove things that make no sense.

* Simplify code.

* Add basic tests.

* Lint.

plugins/doc_fragments/api.py

@@ -0,0 +1,72 @@
+# -*- coding: utf-8 -*-
+
+# Copyright: (c) 2020, Nikolay Dachev <nikolay@dachev.info>
+# GNU General Public License v3.0+ https://www.gnu.org/licenses/gpl-3.0.txt
+
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+
+class ModuleDocFragment(object):
+
+    DOCUMENTATION = r'''
+options:
+  hostname:
+    description:
+      - RouterOS hostname API.
+    required: true
+    type: str
+  username:
+    description:
+      - RouterOS login user.
+    required: true
+    type: str
+  password:
+    description:
+      - RouterOS user password.
+    required: true
+    type: str
+  tls:
+    description:
+      - If is set TLS will be used for RouterOS API connection.
+    required: false
+    type: bool
+    default: false
+    aliases:
+      - ssl
+  port:
+    description:
+      - RouterOS api port. If I(tls) is set, port will apply to TLS/SSL connection.
+      - Defaults are C(8728) for the HTTP API, and C(8729) for the HTTPS API.
+    type: int
+  validate_certs:
+    description:
+      - Set to C(false) to skip validation of TLS certificates.
+      - See also I(validate_cert_hostname). Only used when I(tls=true).
+      - B(Note:) instead of simply deactivating certificate validations to "make things work",
+        please consider creating your own CA certificate and using it to sign certificates used
+        for your router. You can tell the module about your CA certificate with the I(ca_path)
+        option.
+    type: bool
+    default: true
+    version_added: 1.2.0
+  validate_cert_hostname:
+    description:
+      - Set to C(true) to validate hostnames in certificates.
+      - See also I(validate_certs). Only used when I(tls=true) and I(validate_certs=true).
+    type: bool
+    default: false
+    version_added: 1.2.0
+  ca_path:
+    description:
+      - PEM formatted file that contains a CA certificate to be used for certificate validation.
+      - See also I(validate_cert_hostname). Only used when I(tls=true) and I(validate_certs=true).
+    type: path
+    version_added: 1.2.0
+requirements:
+  - librouteros
+  - Python >= 3.6 (for librouteros)
+seealso:
+  - ref: ansible_collections.community.routeros.docsite.api-guide
+    description: How to connect to RouterOS devices with the RouterOS API
+'''