Replace rules_pip with rules_python; use bazel built upstream grpc
instead of Python packages

As usual with Python sadness, the @pydeps wheels are built on the bazel
host, so stuffing them inside a container_image (or py_image) will cause
new and unexpected kinds of misery.

Change-Id: Id4e4d53741cf2da367f01aa15c21c133c5cf0dba
diff --git a/cluster/clustercfg/BUILD b/cluster/clustercfg/BUILD
index eef2049..d83a921 100644
--- a/cluster/clustercfg/BUILD
+++ b/cluster/clustercfg/BUILD
@@ -1,3 +1,5 @@
+load("@pydeps//:requirements.bzl", "requirement")
+
 py_binary(
     name = "clustercfg",
     python_version = "PY3",
@@ -7,7 +9,8 @@
     ],
     visibility = ["//visibility:public"],
     deps = [
-        "@pydeps//fabric",
+        requirement("fabric"),
+        requirement("asn1crypto"),
         "//tools:secretstore_lib",
     ],
 )