Replace crude self-made addon system with Pf4j and provide first entry points

Allow execution of addons before server pack generated, after, before archive creation and allow adding of new tabs in the GUI.

backend/main/java/de/griefed/serverpackcreator/ConfigurationModel.java

@@ -463,36 +463,4 @@ public class ConfigurationModel {
     public void setServerPropertiesPath(String serverPropertiesPath) {
         this.serverPropertiesPath = serverPropertiesPath.replace("\\", "/");
     }
-
-    /**
-     * Concatenates all configuration parameters into a String. Overrides the default toString() method.
-     * @author Griefed
-     * @return String. A concatenated string of the whole configuration.
-     */
-    @Override
-    public String toString() {
-        return "ConfigurationModel{" +
-                "clientMods=" + clientMods +
-                ", copyDirs=" + copyDirs +
-                ", modpackDir='" + modpackDir + '\'' +
-                ", javaPath='" + javaPath + '\'' +
-                ", minecraftVersion='" + minecraftVersion + '\'' +
-                ", modLoader='" + modLoader + '\'' +
-                ", modLoaderVersion='" + modLoaderVersion + '\'' +
-                ", javaArgs='" + javaArgs + '\'' +
-                ", serverPackSuffix='" + serverPackSuffix + '\'' +
-                ", serverIconPath='" + serverIconPath + '\'' +
-                ", serverProperties='" + serverPropertiesPath + '\'' +
-                ", curseModpack=" + curseModpack +
-                ", includeServerInstallation=" + includeServerInstallation +
-                ", includeServerIcon=" + includeServerIcon +
-                ", includeServerProperties=" + includeServerProperties +
-                ", includeZipCreation=" + includeZipCreation +
-                ", projectName='" + projectName + '\'' +
-                ", fileName='" + fileName + '\'' +
-                ", fileDiskName='" + fileDiskName + '\'' +
-                ", projectID=" + projectID +
-                ", fileID=" + fileID +
-                '}';
-    }
 }