chore: cleanr up cards solution code and task description

cards/.classpath

cards/.gitattributes

cards/README.md

cards/build.gradle

cards/gradle/wrapper/gradle-wrapper.jar

cards/gradle/wrapper/gradle-wrapper.properties

cards/gradlew

cards/gradlew.bat

cards/settings.gradle

cards/src/cards/App.java

duplicates/README.md

duplicates/build.gradle

duplicates/gradle/wrapper/gradle-wrapper.jar

duplicates/gradle/wrapper/gradle-wrapper.properties

duplicates/gradlew

duplicates/gradlew.bat

duplicates/settings.gradle

duplicates/src/duplicates/App.java