Added example .env

.env.example

@@ -1,4 +1,17 @@
+# In seconds
+# Default 5 if nothing is provided or
+# invalid value is provided
 RESPONSE_TIMEOUT=5
 
+# A valid port number
+# If not provided or invalid, defaults to 65526
 PORT=65526
-HOST=
+
+# DEBUG, INFO, WARNING, ERROR, CRITICAL are valid
+# If an invalid value is provided, the app defaults to INFO
+VERBOSITY=DEBUG
+
+# Colon (:) separated values.
+# Only two port numbers must be provided
+# Anything else results in an exit
+SCAN_PORT_RANGE=65525:65535