feat: ponies.im emoji support (custom emojum)

src/customemojimodel_p.h

@@ -0,0 +1,19 @@
+// SPDX-FileCopyrightText: 2021 Carson Black <uhhadd@gmail.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "customemojimodel.h"
+
+struct CustomEmoji
+{
+    QString name; // with :semicolons:
+    QString url; // mxc://
+    QRegularExpression regexp;
+};
+
+struct CustomEmojiModel::Private
+{
+    Connection* conn = nullptr;
+    QList<CustomEmoji> emojies;
+};