allow to set a volume as readOnly (apply only in csi driver)

[jagedn]

Add a readOnly method in the VolumeSpec

apply only in csi drivers

Tested against of our nfazure, setting secondary volume as readOnly:

"Volumes": {
        "vol_1": {
          "Name": "",
          "Type": "csi",
          "Source": "nextflow-fs-volume",
          "ReadOnly": true,
          "AccessMode": "multi-node-reader-only",
          "AttachmentMode": "file-system",
          "MountOptions": null,
          "PerAlloc": false
        },
        "vol_0": {
          "Name": "",
          "Type": "csi",
          "Source": "nextflow-fs-volume",
          "ReadOnly": false,
          "AccessMode": "multi-node-multi-writer",
          "AttachmentMode": "file-system",
          "MountOptions": null,
          "PerAlloc": false
        }

closes #60

[abhi18av]

This looks good to merge - thanks @jagedn !

As this PR addresses #60 (by @jhaezebr ) what's the best way to test this? Are you able to build this locally and test or are you relying upon the latest release cycles?

[jagedn]

The snippet attached was generated in the nfazure cluster running our validation/run-all --nfazure script

[abhi18av]

Thanks for highlighting this @jagedn , I think that moving forward @tomiles @matthdsm and @jhaezebr should be able to test the plugin with with --local or --nfazure setup and we can merge this already ✅