Abstract away InstanceCopyPrefs' internals through new getSelectedFiltersAsRegex() function

+ fix typo in comment
+ remove unused import
+ add [[nodiscard]] to methods

Signed-off-by: Marcelo Hernandez <marcelohdez.inq@gmail.com>

launcher/InstanceCopyTask.cpp

@@ -9,62 +9,16 @@ InstanceCopyTask::InstanceCopyTask(InstancePtr origInstance, const InstanceCopyP
 {
     m_origInstance = origInstance;
     m_keepPlaytime = prefs.keepPlaytime;
-    QString filter;
 
-    if(!prefs.copySaves)
+    QString filters = prefs.getSelectedFiltersAsRegex();
+    if (!filters.isEmpty())
     {
-        appendToFilter(filter, "saves");
+        // Set regex filter:
+        // FIXME: get this from the original instance type...
+        auto matcherReal = new RegexpMatcher(filters);
+        matcherReal->caseSensitive(false);
+        m_matcher.reset(matcherReal);
     }
-
-    if(!prefs.copyGameOptions) {
-        appendToFilter(filter, "options.txt");
-    }
-
-    if(!prefs.copyResourcePacks)
-    {
-        appendToFilter(filter, "resourcepacks");
-        appendToFilter(filter, "texturepacks");
-    }
-
-    if(!prefs.copyShaderPacks)
-    {
-        appendToFilter(filter, "shaderpacks");
-    }
-
-    if(!prefs.copyServers)
-    {
-        appendToFilter(filter, "servers.dat");
-        appendToFilter(filter, "servers.dat_old");
-        appendToFilter(filter, "server-resource-packs");
-    }
-
-    if(!prefs.copyMods)
-    {
-        appendToFilter(filter, "coremods");
-        appendToFilter(filter, "mods");
-        appendToFilter(filter, "config");
-    }
-
-    if (!filter.isEmpty())
-    {
-        resetFromMatcher(filter);
-    }
-}
-
-void InstanceCopyTask::appendToFilter(QString& filter, const QString& append)
-{
-    if (!filter.isEmpty())
-        filter.append('|'); // OR regex
-
-    filter.append("[.]?minecraft/" + append);
-}
-
-void InstanceCopyTask::resetFromMatcher(const QString& regexp)
-{
-    // FIXME: get this from the original instance type...
-    auto matcherReal = new RegexpMatcher(regexp);
-    matcherReal->caseSensitive(false);
-    m_matcher.reset(matcherReal);
 }
 
 void InstanceCopyTask::executeTask()