refactor(RD): decouple ResourceModels from ResourcePages

This makes it so that we don't need a reference to the parent page in
the model. It will be useful once we change the page from a widget-based
one to a QML page.

It also makes tasks be created in the dialog instead of the page, so
that the dialog can also have the necessary information to mark versions
as selected / deselected easily. It also makes the task pointers into
smart pointers.

Signed-off-by: flow <flowlnlnln@gmail.com>

launcher/modplatform/ModIndex.h

@@ -65,6 +65,9 @@ struct IndexedVersion {
     QString hash;
     bool is_preferred = true;
     QString changelog;
+
+    // For internal use, not provided by APIs
+    bool is_currently_selected = false;
 };
 
 struct ExtraPackData {
@@ -95,6 +98,23 @@ struct IndexedPack {
     // Don't load by default, since some modplatform don't have that info
     bool extraDataLoaded = true;
     ExtraPackData extraData;
+
+    // For internal use, not provided by APIs
+    [[nodiscard]] bool isVersionSelected(size_t index) const
+    {
+        if (!versionsLoaded)
+            return false;
+
+        return versions.at(index).is_currently_selected;
+    }
+    [[nodiscard]] bool isAnyVersionSelected() const
+    {
+        if (!versionsLoaded)
+            return false;
+
+        return std::any_of(versions.constBegin(), versions.constEnd(),
+                [](auto const& v) { return v.is_currently_selected; });
+    }
 };
 
 }  // namespace ModPlatform