#10 - Creating auxiliary client class to generate configuration class (#78)

* #10 - Creating auxiliary client class to generate configuration class based on cachet's component list.

* Updating the python version in codacy to reduce false positives

* Moving some of the cachet operations to the client class to clean up the configuration class and making better constants

* Refactoring status to have proper classes and adding more tests. Refactoring the requests tests to use requests-mock.

* Removing unused imports from test_scheduler

* Adding more tests and the ability to run the client from command line

* Updating README and client arg parsing

* Fixing broken unit tests

cachet_url_monitor/exceptions.py

@@ -0,0 +1,19 @@
+#!/usr/bin/env python
+class ComponentNonexistentError(Exception):
+    """Exception raised when the component does not exist."""
+
+    def __init__(self, component_id):
+        self.component_id = component_id
+
+    def __str__(self):
+        return repr(f'Component with id [{self.component_id}] does not exist.')
+
+
+class MetricNonexistentError(Exception):
+    """Exception raised when the component does not exist."""
+
+    def __init__(self, metric_id):
+        self.metric_id = metric_id
+
+    def __str__(self):
+        return repr(f'Metric with id [{self.metric_id}] does not exist.')