XYZ-35: Added Support for GlobalRelay Compliance Export Format

* Added username to ChannelMemberHistory struct in anticipation of supporting GlobalRelay in Compliance Export
* Removed translation from debug output - this makes it complicated to use utils functions from tests in the enterprise repo
* Added an advanced email function that allows for greater control over message details. Updated MessageExport config to support GlobalRelay. Added attachment support to InBucket unit tests
* Moving templates in from enterprise to solve test issues
* Added export format to diagnostics
* Changed email attachment code to use FileBackend so that S3 storage is properly supported

utils/inbucket.go

@@ -4,6 +4,7 @@
 package utils
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -37,6 +38,12 @@ type JSONMessageInbucket struct {
 		Text string
 		HTML string `json:"Html"`
 	}
+	Attachments []struct {
+		Filename     string
+		ContentType  string `json:"content-type"`
+		DownloadLink string `json:"download-link"`
+		Bytes        []byte `json:"-"`
+	}
 }
 
 func ParseEmail(email string) string {
@@ -89,21 +96,54 @@ func GetMessageFromMailbox(email, id string) (results JSONMessageInbucket, err e
 	var record JSONMessageInbucket
 
 	url := fmt.Sprintf("%s%s%s/%s", getInbucketHost(), INBUCKET_API, parsedEmail, id)
-	req, err := http.NewRequest("GET", url, nil)
+	emailResponse, err := get(url)
 	if err != nil {
 		return record, err
 	}
+	defer emailResponse.Body.Close()
+
+	err = json.NewDecoder(emailResponse.Body).Decode(&record)
+
+	// download attachments
+	if record.Attachments != nil && len(record.Attachments) > 0 {
+		for i := range record.Attachments {
+			if bytes, err := downloadAttachment(record.Attachments[i].DownloadLink); err != nil {
+				return record, err
+			} else {
+				record.Attachments[i].Bytes = make([]byte, len(bytes))
+				copy(record.Attachments[i].Bytes, bytes)
+			}
+		}
+	}
+
+	return record, err
+}
+
+func downloadAttachment(url string) ([]byte, error) {
+	attachmentResponse, err := get(url)
+	if err != nil {
+		return nil, err
+	}
+	defer attachmentResponse.Body.Close()
+
+	buf := new(bytes.Buffer)
+	io.Copy(buf, attachmentResponse.Body)
+	return buf.Bytes(), nil
+}
+
+func get(url string) (*http.Response, error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
 
 	client := &http.Client{}
-
 	resp, err := client.Do(req)
 	if err != nil {
-		return record, err
+		return nil, err
 	}
-	defer resp.Body.Close()
 
-	err = json.NewDecoder(resp.Body).Decode(&record)
-	return record, err
+	return resp, nil
 }
 
 func DeleteMailBox(email string) (err error) {