chore: clean up solution code

.gitattributes

build.gradle

gradle/wrapper/gradle-wrapper.jar

gradle/wrapper/gradle-wrapper.properties

gradlew

gradlew.bat

settings.gradle

src/main/java/io/fp/shoes/BoxException.java

src/shoes/App.java

src/shoes/Boots.java

src/shoes/Box.java

src/shoes/BoxException.java

src/shoes/Shelf.java

src/shoes/ShoeBox.java

src/shoes/Shoes.java

src/shoes/Sneakers.java

src/test/java/io/fp/shoes/shoeTest.java