add WidgetVariant enum class for widget sizes

app/src/main/java/com/pranshulgg/weather_master_app/widgets/model/WidgetVariant.kt

@@ -0,0 +1,7 @@
+package com.pranshulgg.weather_master_app.widgets.model
+
+enum class WidgetVariant(val label: String) {
+    LARGE("Large"),
+    COMPACT("Compact"),
+    SMALL("Small")
+}