drivers: stepper: api: rename stepper_move to stepper_move_by

rename stepper_move to stepper_move_by in following files:
- include/zephyr/drivers/stepper.h
- include/zephyr/drivers/stepper/stepper_fake.h
- doc/hardware/peripherals/stepper.rst
- doc/releases/migration-guide-4.1.rst
- drivers/stepper/adi_tmc/adi_tmc5041_stepper_controller.c
- drivers/stepper/fake_stepper_controller.c
- drivers/stepper/gpio_stepper_controller.c
- drivers/stepper/stepper_shell.c
- tests/drivers/stepper/shell/src/main.c

Signed-off-by: Jilay Pandya <jilay.pandya@outlook.com>