Refactor Marlin2 component and add new features

- Updated __init__.py to include max_sd_files configuration option.
- Refactored Marlin2 class to use new namespaces and improved structure.
- Added support for binary sensors and select components in binary_sensor.py and select.py.
- Enhanced sensor.py and text_sensor.py to include new configuration options for SD card file count and selected file.
- Improved code readability and organization across multiple files.

text_sensor.py

@@ -7,16 +7,20 @@ from esphome.const import (
 from . import Marlin2
 
 CONF_MARLIN = "marlin2"
-CONFIG_SCHEMA =  cv.Schema(
+CONF_PRINTER_STATE = "printer_state"
+CONF_SD_CARD_FILES = "sd_card_files"
+CONF_SD_CARD_FILE_SELECTED = "sd_card_file_selected"
+
+CONFIG_SCHEMA = cv.Schema(
     {
         cv.GenerateID(CONF_MARLIN): cv.use_id(Marlin2),
-        cv.Optional("printer_state"): text_sensor.text_sensor_schema(
+        cv.Optional(CONF_PRINTER_STATE): text_sensor.text_sensor_schema(
             entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
         ),
-        cv.Optional("sd_card_files"): text_sensor.text_sensor_schema(
+        cv.Optional(CONF_SD_CARD_FILES): text_sensor.text_sensor_schema(
             entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
         ),
-        cv.Optional("sd_card_file_selected"): text_sensor.text_sensor_schema(
+        cv.Optional(CONF_SD_CARD_FILE_SELECTED): text_sensor.text_sensor_schema(
             entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
         ),
     }
@@ -25,7 +29,7 @@ CONFIG_SCHEMA =  cv.Schema(
 async def to_code(config):
     server = await cg.get_variable(config[CONF_MARLIN])
 
-    for sName in ["printer_state", "sd_card_files", "sd_card_file_selected"]:
+    for sName in [CONF_PRINTER_STATE, CONF_SD_CARD_FILES, CONF_SD_CARD_FILE_SELECTED]:
         if sName in config:
             sens = await text_sensor.new_text_sensor(config[sName])
-            cg.add(server.add_text_sensor(sName,sens))
+            cg.add(server.add_text_sensor(sName, sens))