Re-introduce smaller zephyr-runner variants #288
Description
Due to a recent change to the GitHub-hosted runners reducing available disk space, some CI workflows can no longer run on the ubuntu-24.04 runners using the Zephyr CI Docker image.
For example, the doc-build workflow has recently been moved from ubuntu-24.04 to zephyr-runner-v2-linux-4xlarge, which is an overkill for the documentation build job, because of this change.
Re-introduce smaller sized zephyr-runner variants (i.e. < "4xlarge" with 16 vCPUs and 32GB RAM) to allow less CPU-intensive CI workflows to run with the Zephyr CI Docker image.
- zephyr-runner-v2-linux-x64-2xlarge: 8 vCPUs, 16GB RAM
- zephyr-runner-v2-linux-x64-xlarge: 4 vCPUs, 8GB RAM