Set BOOTLOADER = stm32-dfu for all applicable STM32 boards (#12956)

* Set bootloader to stm32-dfu for STM32F303

* Set bootloader to stm32-dfu for STM32F0x2

* Set bootloader to stm32-dfu for STM32F4x1

* Set bootloader to stm32duino for sowbug

* Delete redundant bootloader_defs headers

* Add some missing MCU name comments

* Move APM32 dfu-suffix overrides underneath bootloader

* Remove redundant STM32_BOOTLOADER_ADDRESS defines/rules

keyboards/handwired/onekey/blackpill_f401/rules.mk

@@ -1,8 +1,8 @@
 # MCU name
 MCU = STM32F401
 
-# Address of the bootloader in system memory
-STM32_BOOTLOADER_ADDRESS = 0x1FFF0000
+# Bootloader selection
+BOOTLOADER = stm32-dfu
 
 # Build Options
 #   change yes to no to disable

keyboards/handwired/onekey/blackpill_f411/rules.mk

@@ -1,8 +1,8 @@
 # MCU name
 MCU = STM32F411
 
-# Address of the bootloader in system memory
-STM32_BOOTLOADER_ADDRESS = 0x1FFF0000
+# Bootloader selection
+BOOTLOADER = stm32-dfu
 
 # Build Options
 #   change yes to no to disable

keyboards/handwired/onekey/blackpill_f411_tinyuf2/rules.mk

@@ -1,10 +1,10 @@
 # MCU name
 MCU = STM32F411
 
+# Bootloader selection
+BOOTLOADER = tinyuf2
+
 # Build Options
 #   change yes to no to disable
 #
 KEYBOARD_SHARED_EP       = yes
-
-# We want to use the tinyuf2 bootloader...
-BOOTLOADER = tinyuf2

keyboards/handwired/onekey/proton_c/rules.mk

@@ -1,3 +1,6 @@
 # MCU name
 MCU = STM32F303
 BOARD = QMK_PROTON_C
+
+# Bootloader selection
+BOOTLOADER = stm32-dfu

keyboards/handwired/onekey/stm32f0_disco/rules.mk

@@ -1,6 +1,8 @@
 # MCU name
 MCU = STM32F072
 
+# Bootloader selection
+BOOTLOADER = stm32-dfu
 
 # Enter lower-power sleep mode when on the ChibiOS idle thread
 OPT_DEFS += -DCORTEX_ENABLE_WFI_IDLE=TRUE