style(project): 🎨 improve all docstrings and centralize mail variables in mail_utils

tests/test_models.py

@@ -7,6 +7,7 @@ from logwatcher.models import LogEntry
 
 
 def test_valid_log_entry():
+    """Assert a log entry is correctly created when all arguments are correct."""
     LogEntry(
         server_ip="192.168.13.27",
         mdc_server_name="MDC_720",
@@ -18,6 +19,7 @@ def test_valid_log_entry():
     )
 
 def test_log_entry_invalid_dates():
+    """Assert a log entry cannot be created if start time is not later than error time."""
     with pytest.raises(ValueError, match="Error in date-times"):
         LogEntry(
             server_ip="192.168.13.27",
@@ -30,6 +32,7 @@ def test_log_entry_invalid_dates():
         )
 
 def test_equals_models():
+    """Assert two models are equals if they have the same value as attributes."""
     log_entry_1 = LogEntry(
         server_ip="192.168.13.27",
         mdc_server_name="MDC_720",