GH-1365 rework java version parsing and sorting

logic/java/JavaVersion.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "multimc_logic_export.h"
+#include <QString>
+
+class MULTIMC_LOGIC_EXPORT JavaVersion
+{
+	friend class JavaVersionTest;
+public:
+	JavaVersion() {};
+	JavaVersion(const QString & rhs);
+
+	JavaVersion & operator=(const QString & rhs);
+
+	bool operator<(const JavaVersion & rhs);
+	bool operator==(const JavaVersion & rhs);
+	bool operator>(const JavaVersion & rhs);
+
+	bool requiresPermGen();
+
+	QString toString();
+
+private:
+	QString string;
+	int major = 0;
+	int minor = 0;
+	int security = 0;
+	bool parseable = false;
+	QString prerelease;
+};