Add the benchmarks used to compare cassandra compression algorithm

...lier/cassandra-benchmarks/gatling-directory_ls/.gitignore

vsellier/cassandra-benchmarks/gatling-directory_ls/pom.xml

...s/gatling-directory_ls/src/test/java/BasicSimulation.java

...ling-directory_ls/src/test/resources/directory-1000-1.txt

...ling-directory_ls/src/test/resources/directory-1000-2.txt

...ling-directory_ls/src/test/resources/directory-1000-3.txt

...ling-directory_ls/src/test/resources/directory-1000-4.txt

...ling-directory_ls/src/test/resources/directory-1000-5.txt

...ing-directory_ls/src/test/resources/directory-10000-1.txt

...ing-directory_ls/src/test/resources/directory-10000-2.txt

...ing-directory_ls/src/test/resources/directory-10000-3.txt

...ing-directory_ls/src/test/resources/directory-10000-4.txt

...ng-directory_ls/src/test/resources/directory-100000-1.txt

...ng-directory_ls/src/test/resources/directory-200000-1.txt

...chmarks/gatling-directory_ls/src/test/resources/local.txt

...-benchmarks/random-directories/get-random-directory-id.py

.../cassandra-benchmarks/random-directories/requirements.txt