Add comments to the new configuration classes.

core/src/main/kotlin/org/nwapw/abacus/config/Configuration.kt

@@ -1,7 +1,20 @@
 package org.nwapw.abacus.config
 
+/**
+ * A class that holds information that tells Abacus how to behave.
+ *
+ * Configuration stores information about how Abacus should behave, for
+ * instance, what number implementation it should use and what
+ * plugins should be ignored during loading.
+ *
+ * @property numberImplementation the number implementation Abacus should use for loading.
+ * @param disabledPlugins the plugins that should be disabled and not loaded by the plugin manager.
+ */
 open class Configuration(var numberImplementation: String = "<default>", disabledPlugins: Array<String> = emptyArray()) {
 
+    /**
+     * The set of disabled plugins that should be ignored by the plugin manager.
+     */
     val disabledPlugins = disabledPlugins.toMutableSet()
 
 }