restructure converters (#1825)

* restructure converters

each converter is its own keyboard and different hardware variants are different subprojects.

remove (seemingly) old method of loading layouts from main Makefile

* call led_set_kb() from overridden led_set()

* put converter back into one folder

* revert some structure changes to bring in line with #1784.

Also attempt to get the BLE thing more properly integrated.
Also also fix led_set() to call led_set_kb().

keyboards/converter/usb_usb/ble/config.h

@@ -0,0 +1,13 @@
+#ifndef CONFIG_BLE_H
+#define CONFIG_BLE_H
+
+#undef PRODUCT
+#define PRODUCT         QMK BLE Adapter
+#undef DESCRIPTION
+#define DESCRIPTION  
+
+// Turn off the mode leds on the BLE module
+#define ADAFRUIT_BLE_ENABLE_MODE_LEDS 0
+#define ADAFRUIT_BLE_ENABLE_POWER_LED 0
+
+#endif