Remove the embedded launch script configuration

Spring Boot 4.0 removed support for embedding a launch script that makes jars and wars directly executable. Removes the Gradle build script statements that use launchScript(), which no longer compile, and marks a use in the unbraced body of an if, else or loop for manual migration. Also removes the executable, embeddedLaunchScript and embeddedLaunchScriptProperties parameters of the spring-boot-maven-plugin, which Maven ignores. Start the application with java -jar instead.