Add microfuchsia apex that runs in AVF on bootup

This requires another apex com.android.microfuchsia.images to be present
that contains a /etc/fuchsia.zbi and /etc/linux-arm64-boot-shim.bin.

Test: Boot up and use console with:
  adb shell -t /apex/com.android.virt/bin/vm console
Bug: b/348687281, b/348434277, b/348433755
Change-Id: I3fe0674d793d37763011f102982f5c3e56b57b5e
diff --git a/microfuchsia/apex/com.android.microfuchsia-file_contexts b/microfuchsia/apex/com.android.microfuchsia-file_contexts
new file mode 100644
index 0000000..13d7286
--- /dev/null
+++ b/microfuchsia/apex/com.android.microfuchsia-file_contexts
@@ -0,0 +1,2 @@
+(/.*)?                   u:object_r:system_file:s0
+/bin/microfuchsiad       u:object_r:microfuchsiad_exec:s0