CI: add fast precheck step

Adds a preliminary step to check OTB can build on a Ubuntu-native image with a warm ccache. The cache is generated on develop branch. In the future, the image will be updated regularly. No test, no data for this job.

About twin pipelines: there is a python script to cancel twin pipelines (single push triggers one normal pipeline and a merge request pipeline). Here is the logic of the script:

• Are we in a Merge-Request pipeline?
• Yes:
  • Is it a "Wip" merge request?
  • Yes:
    • cancel this pipeline, let the "normal" pipeline continue
  • No:
    • cancel the "normal" pipeline