[cbor] Separate cbor conversion functions in an independent lib

This allows callers from both std and nostd environment to
convert to/from CBOR-encoded data.

Bug: 303807447
Test: atest libservice_vm_requests.test
Change-Id: Ib2052f28779290165941cb2cf7ecc9ca566472af
diff --git a/service_vm/requests/Android.bp b/service_vm/requests/Android.bp
index f85064a..ecede8b 100644
--- a/service_vm/requests/Android.bp
+++ b/service_vm/requests/Android.bp
@@ -18,6 +18,7 @@
     rustlibs: [
         "libbssl_avf_error_nostd",
         "libbssl_avf_nostd",
+        "libcbor_util_nostd",
         "libciborium_nostd",
         "libcoset_nostd",
         "libdiced_open_dice_nostd",