Create a WvCasStatus to be used as return type of libraries in media_cas_packager_sdk.

Following example: []/video/widevine/export/provisioning_sdk/public/provisioning_status.h
and
[]/video/widevine/export/exported_root/util/status.h

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=218918745

example/BUILD

@@ -47,7 +47,8 @@ cc_binary(
     name = "wv_cas_ecm_example",
     srcs = ["wv_cas_ecm_example.cc"],
     deps = [
-        "//base",
+        "@abseil_repo//absl/base:core_headers",
         "//media_cas_packager_sdk/public:wv_cas_ecm",
+        "//media_cas_packager_sdk/public:wv_cas_status",
     ],
 )