The "Practice60" Board, Blue Pill powered (#4407)

* Starting point for blue pill based practice60

* Changes

* add

* try raw bin no botloader

* swap back to bootloader version

* edit

* Remove debug LED flash

* Disable JTAG to open up B3 and B4

* Add led backlight support (no breathing yet)

* Update matrix for correctness

* RGB Underglow working in a very simple state

* not as bright

* Move to handwired

* revert ChibiOS_Test changes

* Changes based on PR comments

* Address PR comments v2

* Move files

keyboards/handwired/practice60/bootloader_defs.h

@@ -0,0 +1,10 @@
+/* Address for jumping to bootloader on STM32 chips. */
+/* It is chip dependent, the correct number can be looked up here (page 175):
+ * http://www.st.com/web/en/resource/technical/document/application_note/CD00167594.pdf
+ * This also requires a patch to chibios:
+ *  <tmk_dir>/tmk_core/tool/chibios/ch-bootloader-jump.patch
+ */
+
+// STM32F103* does NOT have an USB bootloader in ROM (only serial),
+//  so setting anything here does not make much sense
+// #define STM32_BOOTLOADER_ADDRESS 0x1FFFC800