The `dfu-util` command uses `--device $(DFU_USB_ID)`, where `DFU_USB_ID` is derived from `USB_VID` and `USB_PID` to specify the DFU device to use. Without specifying `USB_VID` and `USB_PID` in the make command, `dfu-util` is called with `--device :`, which only works if there is only one DFU device. Also, the STM32 make system forbids the use of `dfu-util` as programmer without setting the variable `DFU_USB_ID`. Therefore, the documentation is changed to use `USB_VID`/`USB_PID` or `DFU_USB_ID` in the make command.
To avoid confusions between `auto_init_ztimer` and `ztimer_auto_init`
rename `ztimer_auto_init` to `ztimer_init`.
This allows for similar handling as `saul_init_devs` and
`auto_init_devs`. Dependencies are therefore done against the USEMODULE
and not DEFAULT_MODULE or checking DISABLE_MODULE. For this, both
`ztimer_init` and `auto_init_ztimer` are added to DEFAULT_MODULE and
both need disabling if the user does not want that module in.
With this, the comment in Kconfig no longer applies.
The IDs are not advertised to dfu-util to allow a smooth transition into
having a VID/PID-identifiable riotboot_dfu.
As allocated on https://pid.codes/1209/7D02/.
