Updated for support for msg format.

Adding first class support for Emails in .msg format to the email definition.
This includes making the  attribute support multiple bodies. Msg formats
nearly always have at least 2, if not 3, versions of the body (plain text, rtf, html).

objects/email/definition.json

@@ -26,6 +26,7 @@
       "description": "Body of the email",
       "disable_correlation": true,
       "misp-attribute": "email-body",
+      "multiple": true,
       "ui-priority": 1
     },
     "eml": {
@@ -34,6 +35,12 @@
       "misp-attribute": "attachment",
       "ui-priority": 1
     },
+    "msg": {
+      "description": "Full MSG",
+      "disable_correlation": true,
+      "misp-attribute": "attachment",
+      "ui-priority": 1
+    },
     "from": {
       "categories": [
         "Payload delivery"
@@ -204,7 +211,8 @@
     "x-mailer",
     "return-path",
     "email-body",
-    "eml"
+    "eml",
+    "msg"
   ],
   "uuid": "a0c666e0-fc65-4be8-b48f-3423d788b552",
   "version": 15