eve/email: log existing url type

MIME parsing was setting flag on URL to indicate their
estimated type. This patch attach the information to
the email object so the user can extract interesting
email directly:

```
  "email": {
    "status": "PARSE_DONE",
    "from": "Eric Leblond <regit@regit.org>",
    "to": [
      "eric@regit.org"
    ],
    "has_ipv6_url": false,
    "has_ipv4_url": false,
    "has_exe_url": true,
    "url": [
      "http://www.toto.com",
      "http://perdu.com.",
      "https://hacke.me/pown.exe"
    ]
  }
```

src/output-json-email-common.c

@@ -292,15 +292,27 @@ static bool EveEmailLogJsonData(const Flow *f, void *state, void *vtx, uint64_t
         JsonBuilder *js_url = jb_new_array();
         if (entity->url_list != NULL) {
             MimeDecUrl *url;
+            bool has_ipv6_url = false;
+            bool has_ipv4_url = false;
+            bool has_exe_url = false;
             for (url = entity->url_list; url != NULL; url = url->next) {
                 char *s = BytesToString((uint8_t *)url->url,
                                         (size_t)url->url_len);
                 if (s != NULL) {
                     jb_append_string(js_url, s);
+                    if (url->url_flags & URL_IS_EXE)
+                        has_exe_url = true;
+                    if (url->url_flags & URL_IS_IP6)
+                        has_ipv6_url = true;
+                    if (url->url_flags & URL_IS_IP4)
+                        has_ipv6_url = true;
                     SCFree(s);
                     url_cnt += 1;
                 }
             }
+            jb_set_bool(sjs, "has_ipv6_url", has_ipv6_url);
+            jb_set_bool(sjs, "has_ipv4_url", has_ipv4_url);
+            jb_set_bool(sjs, "has_exe_url", has_exe_url);
         }
         for (entity = entity->child; entity != NULL; entity = entity->next) {
             if (entity->ctnt_flags & CTNT_IS_ATTACHMENT) {