[MOD] Add x-parsee tag with metadata, global nicks

Still need to grab it on the room-level from the room state if possible,
otherwise just rollback to the MXID.

I also need to consider profile pictures and bridging media, and check
if the nick was present XMPP-side first, as that can and will cause
issues, especially around semi-anonymous MUCs.

src/AS.c

@@ -280,3 +280,44 @@ ASSetName(const ParseeConfig *conf, char *user, char *name)
     JsonFree(json);
     Free(user);
 }
+char *
+ASGetName(const ParseeConfig *c, char *room, char *user)
+{
+    HttpClientContext *ctx;
+    HashMap *reply;
+    char *path, *ret;
+    if (!c || !user)
+    {
+        return NULL;
+    }
+
+    if (!room)
+    {
+        user = HttpUrlEncode(user);
+        path = StrConcat(3,
+            "/_matrix/client/v3/profile/", user, "/displayname"
+        );
+        ctx = ParseeCreateRequest(c, HTTP_GET, path);
+        Free(user);
+        ASAuthenticateRequest(c, ctx);
+        HttpRequestSendHeaders(ctx);
+        HttpRequestSend(ctx);
+
+        reply = JsonDecode(HttpClientStream(ctx));
+
+        JsonFree(reply);
+        ret = StrDuplicate(
+            JsonValueAsString(HashMapGet(reply, "displayname"))
+        );
+        HttpClientContextFree(ctx);
+        Free(path);
+
+        if (!ret)
+        {
+            ret = StrDuplicate(user);
+        }
+        return ret;
+    }
+
+    return NULL;
+}