[Core] Add support for RISC-V builds and GD32VF103 MCU (#12508)

* Add support for RISC-V builds and GD32VF103 MCU

* Add toolchain selection in chibios.mk based on the mcu selected in
mcu_selection.mk
* Reorder and added comments to chibios.mk to have a streamlined makefile
* Add GD32VF103 mcu to possible targets for QMK.
* Add STM32 compatibility for GD32VF103 MCU, this is hacky but more efficent
  then rewriting every driver.
* Add GigaDevice DFU bootloader as flash target, please note that
  dfu-util of at least version 0.10 is needed.
* Add analog driver compatibility
* Add apa102 bitbang driver compatibility
* Add ws2812 bitbang driver compatibility
* Add eeprom in flash emulation compatibility
* Allow faster re-builds with ccache

* Add SiPeed Longan Nano to platform files

* Add SiPeed Longan Nano Onekeys

* Make quine compatible with other bootloaders

* Support builds with picolibc

* Add risc-v toolchain to arch and debian/ubuntu scripts

keyboards/handwired/onekey/sipeed_longan_nano/mcuconf.h

@@ -0,0 +1,29 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
+    ChibiOS - Copyright (C) 2021 Stefan Kerkmann
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+#pragma once
+
+#include_next <mcuconf.h>
+
+#undef GD32_ADC_USE_ADC0
+#define GD32_ADC_USE_ADC0 TRUE
+
+#undef GD32_I2C_USE_I2C0
+#define GD32_I2C_USE_I2C0 TRUE
+
+#undef GD32_PWM_USE_TIM4
+#define GD32_PWM_USE_TIM4 TRUE