Revert "Remove enabledFeatures from the default configuration; it is useless"

This reverts commit 92a3bae74a59cf59c6a9fabbaa42e925cded899a.

common/src/main/kotlin/fr/username404/snowygui/config/Configuration.kt

@@ -52,6 +52,9 @@ object Configuration {
                 """
                     |Snowy {
                     |  displayInitMessage = true
+                    |  enabledFeatures {
+                    |    GammaBoost = false
+                    |  }
                     |}
                 """.trimMargin()
             )
@@ -78,4 +81,4 @@ object Configuration {
             }
         )
     }
-}
+}