* update of the whole pipeline
* add explanation comments
* change approach to skip tests on documentation changes
* add smaller expiration time for artifacts

Packaging:
* tags will trigger the package building
* add package testing after build
* Publish the package on devel channel if TAGS contains 'rc' else to
stable channel

Pages:
* tags and master will trigger Documentation Pages deploy
* Keeps different version of pages adding a root directory to
documentation website, master documentation will be unter /master/
tagged version wil be under /tag/