Convert to external .fap; export ST BLE command API from the firmware

build.sh now adds ST's aci_*/hci_* headers to the SDK (with extern "C"
guards, the API table is C++), lets fbt regenerate api_symbols.csv and
enables the selected functions (BLE_API=hci,gatt default; min; all).
The app builds as a normal .fap shipped inside the update package and
loadable from SD, saving ~12 KB of firmware flash versus the built-in
(min mode: ~22 KB). qsort replaced with an insertion sort since libc's
qsort is not exported to apps. README documents modes and flash budget.

bt_inspector/bt_inspector.c

@@ -10,7 +10,7 @@
 #include <gui/modules/text_input.h>
 #include <gui/modules/number_input.h>
 #include <storage/storage.h>
-#include <ble/ble.h>
+#include <ble/core/ble_defs.h>
 #include <string.h>
 #include <stdarg.h>
 #include "ble_central.h"