drivers: sensor: remove example sensor driver and related config

- Delete out-of-tree example_sensor driver and its Kconfig/CMake files
- Remove references to CONFIG_SENSOR and example_sensor from prj.conf,
  drivers/Kconfig, and drivers/CMakeLists.txt

Refs: #4

Signed-off-by: Natalia Pluta <pluta.natalia.m@gmail.com>

Author: nmpluta

app/prj.conf

@@ -1,10 +1,9 @@
-# Copyright (c) 2021 Nordic Semiconductor ASA
+# Copyright (c) 2025 Natalia Pluta
 # SPDX-License-Identifier: Apache-2.0
 #
 # This file contains selected Kconfig options for the application.
 
 CONFIG_LOG=y
-CONFIG_SENSOR=y
 CONFIG_BLINK=y
 
 # Enable I2C and sensor subsystem for BME280

drivers/CMakeLists.txt

@@ -3,6 +3,3 @@
 
 # Out-of-tree drivers for custom classes
 add_subdirectory_ifdef(CONFIG_BLINK blink)
-
-# Out-of-tree drivers for existing driver classes
-add_subdirectory_ifdef(CONFIG_SENSOR sensor)

drivers/Kconfig

@@ -3,5 +3,4 @@
 
 menu "Drivers"
 rsource "blink/Kconfig"
-rsource "sensor/Kconfig"
 endmenu