core/zero: add usage reporter (#5281)

* wip

* add response

* handle empty email

* use set, update log

* add test

* add coalesce, comments, test

* add test, fix bug

* use builtin cmp.Or

* remove wait ready call

* use api error

pkg/cryptutil/pseudonymize.go

@@ -0,0 +1,16 @@
+package cryptutil
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"io"
+)
+
+// Pseudonymize pseudonymizes data by computing the HMAC-SHA256 of the data.
+func Pseudonymize(organizationID string, data string) string {
+	h := hmac.New(sha256.New, []byte(organizationID))
+	_, _ = io.WriteString(h, data)
+	bs := h.Sum(nil)
+	return base64.StdEncoding.EncodeToString(bs)
+}