[CI] config & badges

.gitlab-ci.yml

+include: http://rainboard.laas.fr/project/hpp-practicals/.gitlab-ci.yml

README.md

+# HPP Practicals
+
+[![Pipeline status](https://gepgitlab.laas.fr/humanoid-path-planner/hpp-practicals/badges/master/pipeline.svg)](https://gepgitlab.laas.fr/humanoid-path-planner/hpp-practicals/commits/master)
+[![Coverage report](https://gepgitlab.laas.fr/humanoid-path-planner/hpp-practicals/badges/master/coverage.svg?job=doc-coverage)](http://projects.laas.fr/gepetto/doc/humanoid-path-planner/hpp-practicals/master/coverage/)
+