[WIP] Attempt at building grpc and p4runtime protocols with Bazel

STILL NOT WORKING AT RUNTIME

Change-Id: I1f9e60b12a12e09edad2a714ec2921a4f71c6d35
diff --git a/tools/build/bazel/protobuf_workspace.bzl b/tools/build/bazel/protobuf_workspace.bzl
new file mode 100644
index 0000000..1932b57
--- /dev/null
+++ b/tools/build/bazel/protobuf_workspace.bzl
@@ -0,0 +1,13 @@
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+PROTOBUF_VER = "3.6.1"
+SHA = "0a4c6d0678eb2f063df332cff1a41647ef692c067b5cfb19e51bca778e79d9e0"
+
+def generate_protobuf():
+    http_archive(
+        name = "com_google_protobuf",
+        urls = ["https://github.com/google/protobuf/releases/download/v%s/protobuf-all-%s.zip"
+            % (PROTOBUF_VER, PROTOBUF_VER)],
+        sha256 = SHA,
+        strip_prefix = "protobuf-" + PROTOBUF_VER,
+    )