feat(bluetooth): Add back profiles, split fixes.

* Add back in profiles, not using Zephyr
  BT identity infrastructure.
* Restore additional `&bt` commands for profile
  operations.
* Fix for split pairing and subscriptions, since
  Zephyr persists subscriptions across connects.
* Remove keymap from peripheral builds, reduces
  firmware size, and avoids unneeded attempts
  to send HID data.

app/src/events/ble_active_profile_changed.c

@@ -0,0 +1,10 @@
+/*
+ * Copyright (c) 2020 Peter Johanson <peter@peterjohanson.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <kernel.h>
+#include <zmk/events/ble-active-profile-changed.h>
+
+ZMK_EVENT_IMPL(ble_active_profile_changed);