Introduce vintf_fragment module type

Introduce a new vintf_fragment module type which handles vintf_fragment
files within Soong. This will help process to move vintf_fragment
handling logic from KATI to Soong. This change also introduces
vintf_fragment_modules property to mark dependency with vintf_fragment
modules.

Bug: 322089980
Test: m nothing --no-skip-soong-tests passed
Change-Id: I49607f42aeee3ded0ba7b078b903dc35f5d61637
diff --git a/android/Android.bp b/android/Android.bp
index 841a6af..96e8133 100644
--- a/android/Android.bp
+++ b/android/Android.bp
@@ -106,6 +106,7 @@
         "updatable_modules.go",
         "util.go",
         "variable.go",
+        "vintf_fragment.go",
         "visibility.go",
     ],
     testSrcs: [
@@ -148,6 +149,7 @@
         "test_suites_test.go",
         "util_test.go",
         "variable_test.go",
+        "vintf_fragment_test.go",
         "visibility_test.go",
     ],
 }