feat: add very early mod.toml packwiz support

Also use it as a on-disk format for storing mod metadata. This will be
used later on to make better mod managment.

launcher/modplatform/packwiz/Packwiz.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <QString>
+#include <QUrl>
+#include <QVariant>
+
+namespace ModPlatform {
+enum class Provider;
+class IndexedPack;
+class IndexedVersion;
+}  // namespace ModPlatform
+
+class QDir;
+
+class Packwiz {
+   public:
+    struct Mod {
+        QString name;
+        QString filename;
+        // FIXME: make side an enum
+        QString side = "both";
+
+        // [download]
+        QUrl url;
+        // FIXME: make hash-format an enum
+        QString hash_format;
+        QString hash;
+
+        // [update]
+        ModPlatform::Provider provider;
+        QVariant file_id;
+        QVariant project_id;
+    };
+
+    /* Generates the object representing the information in a mod.toml file via its common representation in the launcher */
+    static auto createModFormat(QDir& index_dir, ModPlatform::IndexedPack& mod_pack, ModPlatform::IndexedVersion& mod_version) -> Mod;
+
+    /* Updates the mod index for the provided mod.
+     * This creates a new index if one does not exist already
+     * TODO: Ask the user if they want to override, and delete the old mod's files, or keep the old one.
+     * */
+    static void updateModIndex(QDir& index_dir, Mod& mod);
+};