Update pagerduty modules to rest v2 (#42618)

* refactored from procedural to OOP

* updated ongoing maintenance windows to PagerDuty REST API v2

* update create maintenance windows to PagerDuty REST API v2

* update absent maintenance windows to PagerDuty REST API v2

* update pager alert module to PagerDuty REST API v2

* removed basic HTTP authorization
updated parameter description and examples

* fix failed sanity checks

* revised documentation according to review

* make obsolete service key parameter an alias to a new integration key parameter

test/units/modules/monitoring/test_pagerduty_alert.py

@@ -0,0 +1,41 @@
+from ansible.compat.tests import unittest
+from ansible.modules.monitoring import pagerduty_alert
+
+from ansible.module_utils.six.moves.urllib.parse import urlparse, urlencode, urlunparse
+
+
+class PagerDutyAlertsTest(unittest.TestCase):
+    def _assert_incident_api(self, module, url, method, headers):
+        self.assertTrue('https://api.pagerduty.com/incidents' in url, 'url must contain REST API v2 network path')
+        self.assertTrue('service_ids%5B%5D=service_id' in url, 'url must contain service id to filter incidents')
+        self.assertTrue('sort_by=incident_number%3Adesc' in url, 'url should contain sorting parameter')
+        self.assertTrue('time_zone=UTC' in url, 'url should contain time zone parameter')
+        return Response(), {'status': 200}
+
+    def _assert_compatibility_header(self, module, url, method, headers):
+        self.assertDictContainsSubset(
+            {'Accept': 'application/vnd.pagerduty+json;version=2'},
+            headers,
+            'Accept:application/vnd.pagerduty+json;version=2 HTTP header not found'
+        )
+        return Response(), {'status': 200}
+
+    def _assert_incident_key(self, module, url, method, headers):
+        self.assertTrue('incident_key=incident_key_value' in url, 'url must contain incident key')
+        return Response(), {'status': 200}
+
+    def test_incident_url(self):
+        pagerduty_alert.check(None, 'name', 'state', 'service_id', 'integration_key', 'api_key', http_call=self._assert_incident_api)
+
+    def test_compatibility_header(self):
+        pagerduty_alert.check(None, 'name', 'state', 'service_id', 'integration_key', 'api_key', http_call=self._assert_compatibility_header)
+
+    def test_incident_key_in_url_when_it_is_given(self):
+        pagerduty_alert.check(
+            None, 'name', 'state', 'service_id', 'integration_key', 'api_key', incident_key='incident_key_value', http_call=self._assert_incident_key
+        )
+
+
+class Response(object):
+    def read(self):
+        return '{"incidents":[{"id": "incident_id", "status": "triggered"}]}'