Allow Users to Select Specific sets of Gitlab Runners for pipelines

Issue:

Needs to run CI on different platform, configuration and architecture. Because the nature of their differences, each configuration need their own physical machine with their own Gitlab Runner. Currently the CI jobs is sent to which ever Runner is available, without taking into account their differences.

Solution:

Allow user to specify a set of Runners that needs to run (i.e, x86, ARMx64, amd64, ppcle64, NVIDIA-gpu, AMD-gpu, ...). Note that all those different platform might need a different docker image as well as a starting point.

It might be nice to have each of those configuration explicitly in the .gitlab-ci.yml so gitlab can dispatch the jobs to the correct runner.