Merge branch '114-diamond-kata' into 'master'

.gitlab-ci.yml

java-diamond/.gitlab-ci.yml

java-diamond/pom.xml

java-diamond/readme.md

java-diamond/src/main/java/fr/craft/kata/Diamond.java

java-diamond/src/main/java/fr/craft/kata/Line.java

java-diamond/src/test/java/fr/craft/kata/DiamondTest.java

java-diamond/src/test/java/fr/craft/kata/LineTest.java

java-diamond/src/test/resources/a.txt

java-diamond/src/test/resources/b.txt

java-diamond/src/test/resources/c.txt

java-diamond/src/test/resources/d.txt

readme.md