Ci/basic linux and osx

Create simple commun CI script (linux, osx, windows) than can be used by lidarview's application via:

include:
  - project: 'LidarView/lidarview-core'
    file: 'CI/.gitlab-ci.yml'
    ref: master

see this example

This script can be used in complement to the script in the lidarview app repository. But it will eventually replace them.

TODO in another MR:

• linux support
• osx support
• windows support
• add possibility to specify build configuration? (pcl, ceres, ..)