VNDK APEX contains related *.libraries.txt files

These files were highly coupled with vndk version, so having them inside
the corresponding VNDK APEX is reasonable.

These files are used by linkerconfig and libnativeloader. In the future,
they reference these files from and VNDK APEX.

Bug: 141450808
Test: m com.android.vndk.current
Change-Id: I055a979d2636ddd8844a0afff81f6ba441f7965e

android/prebuilt_etc.go

@@ -54,6 +54,12 @@ type prebuiltEtcProperties struct {
 	Installable *bool
 }
 
+type PrebuiltEtcModule interface {
+	Module
+	SubDir() string
+	OutputFile() OutputPath
+}
+
 type PrebuiltEtc struct {
 	ModuleBase