Move the qt models to their own folder

Felt like the src folder was getting a bit crowded so move all the models to a folder named models.

src/models/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"
+#include <QRegularExpression>
+#include <connection.h>
+
+struct CustomEmoji {
+    QString name; // with :semicolons:
+    QString url; // mxc://
+    QRegularExpression regexp;
+};
+
+struct CustomEmojiModel::Private {
+    Quotient::Connection *conn = nullptr;
+    QList<CustomEmoji> emojies;
+};