Add cli property for forced keywords

src/main/java/at/pcgamingfreaks/mkvaudiosubtitlechanger/model/ConfigProperty.java

@@ -0,0 +1,22 @@
+package at.pcgamingfreaks.mkvaudiosubtitlechanger.model;
+
+public enum ConfigProperty {
+    MKV_TOOL_NIX("mkvtoolnixPath"),
+    THREADS("threads"),
+    FORCED_KEYWORDS("forcedKeywords"),
+    CONFIG("config"),
+    LIBRARY("library"),
+    SAFE_MODE("safe-mode"),
+    HELP("help");
+
+    private String property;
+
+    ConfigProperty(String property) {
+        this.property = property;
+    }
+
+    @Override
+    public String toString() {
+        return property;
+    }
+}