authfs: Support binder-backed file source

This change adds remote file support to authfs. This allows a process to
read a remote file through a local path with transparent fs-verity
verification.

This is supposed to work across VM boundary, but before the remote
binder is ready, this change uses local binder.

Test: Shell #1
      $ adb shell 'exec
          9</system/bin/sh
          8</data/local/tmp/input.4m
          7</data/local/tmp/input.4m.merkle_dump
          6</data/local/tmp/input.4m.fsv_sig

          fd_server
          --ro-fds 9
          --ro-fds 8:7:6'`
      Shell #2
      $ adb push tools/device-test.sh /data/local/tmp/ && \
        adb shell /data/local/tmp/device-test.sh

Change-Id: Ia69fae548b83ff3ba572f4a496a7cbcca518cbef
diff --git a/authfs/Android.bp b/authfs/Android.bp
index 3fc4504..9f7be93 100644
--- a/authfs/Android.bp
+++ b/authfs/Android.bp
@@ -10,6 +10,7 @@
     ],
     edition: "2018",
     rustlibs: [
+        "authfs_aidl_interface-rust",
         "libanyhow",
         "libauthfs_crypto_bindgen",
         "libcfg_if",