bluetooth: convert to apex

* Use device as an identifier in package names so APEXs on rpi4/rpi5 trees
  can co-exist. Somehow apex definitions escape the soong namespace. It
  doesn't complain about duplicate package names but dependecies later in
  the build after analyzing Android.bp files and generating ninja file.
  FAILED: ninja: ... multiple rules generate com.android.hardware.bluetooth.rpi-deps-info [-w dupbuild=err]
  https://android.googlesource.com/platform/build/soong/+/refs/heads/main/README.md#namespaces
* Not sure if this is an AOSP bug or intended behaviour for apex targets.
  Don't like using the rpi4/rpi5 tags but couldn't come up with better
  solution to limit the visibility that worked.
* General cleanups. As APEX package contains all dependencies that are
  needed for the service, remove unused shared libraries.
  Run 'bpfmt -s -w Android.bp'.

bluetooth/apex_file_contexts

@@ -0,0 +1,3 @@
+(/.*)?                                             u:object_r:vendor_file:s0
+/etc(/.*)?                                         u:object_r:vendor_configs_file:s0
+/bin/hw/android\.hardware\.bluetooth-service\.rpi  u:object_r:hal_bluetooth_default_exec:s0