refactor: add instance creation abstraction and move vanilla

This is so that 1. Code is more cleanly separated, and 2. Allows to more
easily add instance updating :)

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

launcher/minecraft/VanillaInstanceCreationTask.cpp

@@ -0,0 +1,32 @@
+#include "VanillaInstanceCreationTask.h"
+
+#include "FileSystem.h"
+#include "settings/INISettingsObject.h"
+#include "minecraft/MinecraftInstance.h"
+#include "minecraft/PackProfile.h"
+
+VanillaCreationTask::VanillaCreationTask(BaseVersionPtr version, QString loader, BaseVersionPtr loader_version)
+    : InstanceCreationTask(), m_version(version), m_using_loader(true), m_loader(loader), m_loader_version(loader_version)
+{}
+
+bool VanillaCreationTask::createInstance()
+{
+    setStatus(tr("Creating instance from version %1").arg(m_version->name()));
+
+    auto instance_settings = std::make_shared<INISettingsObject>(FS::PathCombine(m_stagingPath, "instance.cfg"));
+    instance_settings->suspendSave();
+    {
+        MinecraftInstance inst(m_globalSettings, instance_settings, m_stagingPath);
+        auto components = inst.getPackProfile();
+        components->buildingFromScratch();
+        components->setComponentVersion("net.minecraft", m_version->descriptor(), true);
+        if(m_using_loader)
+            components->setComponentVersion(m_loader, m_loader_version->descriptor());
+
+        inst.setName(m_instName);
+        inst.setIconKey(m_instIcon);
+    }
+    instance_settings->resumeSave();
+
+    return true;
+}

launcher/minecraft/VanillaInstanceCreationTask.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "InstanceCreationTask.h"
+
+class VanillaCreationTask final : public InstanceCreationTask {
+    Q_OBJECT
+   public:
+    VanillaCreationTask(BaseVersionPtr version) : InstanceCreationTask(), m_version(version) {}
+    VanillaCreationTask(BaseVersionPtr version, QString loader, BaseVersionPtr loader_version);
+
+    bool createInstance() override;
+
+   private:
+    // Version to update to / create of the instance.
+    BaseVersionPtr m_version;
+
+    bool m_using_loader = false;
+    QString m_loader;
+    BaseVersionPtr m_loader_version;
+};