Suppress full config output of "esphome config" when -q option is used. (#5852)

esphome/core/__init__.py

@@ -522,6 +522,8 @@ class EsphomeCore:
         self.component_ids = set()
         # Whether ESPHome was started in verbose mode
         self.verbose = False
+        # Whether ESPHome was started in quiet mode
+        self.quiet = False
 
     def reset(self):
         self.dashboard = False