feat(Start scripts): Templating! Create start scripts from customizable templates

...a/de/griefed/serverpackcreator/ApplicationProperties.java

...va/de/griefed/serverpackcreator/ConfigurationHandler.java

...java/de/griefed/serverpackcreator/ConfigurationModel.java

.../java/de/griefed/serverpackcreator/ServerPackCreator.java

.../java/de/griefed/serverpackcreator/ServerPackHandler.java

...erpackcreator/spring/serverpack/ServerPackController.java

.../griefed/serverpackcreator/swing/TabCreateServerPack.java

...es/de/griefed/resources/server_files/default_template.ps1

...ces/de/griefed/resources/server_files/default_template.sh

backend/main/resources/serverpackcreator.properties

.../griefed/serverpackcreator/ApplicationPropertiesTest.java

...a/de/griefed/serverpackcreator/ServerPackCreatorTest.java

...a/de/griefed/serverpackcreator/ServerPackHandlerTest.java

frontend/package-lock.json

frontend/package.json