audiopolicy: Convert some of .mk files to .bp files

- Renamed libaudiopolicyengineconfig to libaudiopolicyengine_config
  in order to match names libaudiopolicyengine_{common|interface}.

- Made libaudiopolicyengine_config static to avoid .so overhead.

- Added a cleanspec for it.

- Added libaudiopolicyengine_common which includes source files
  previously included directly into engineconfigurable and
  enginedefault libraries.

Bug: 121208203
Test: make & flash crosshatch
Change-Id: If3b7b89fcbd5752ddfdeca6c164a88f55bc35811
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 793cbf4..e584ffb 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -81,6 +81,7 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/lib/libstagefright_xmlparser@1.0.so)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/lib/libstagefright_soft_*)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/lib/vndk/libstagefright_soft_*)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/lib/libaudiopolicyengineconfig*)
 
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST