Image-builder: Update kernel and keep only 1 kernel on redhat machines

[vignesh-goutham]

Description of changes:
Image builder was excluding kernel updates till now. With this change, image builder will update kernels and reboot into the new kernel. Post reboot, if the OS has more than 1 kernel, this change will remove all non-live kernels running on the RHEL machine.

Testing
Running image builder with changes output

    qemu: TASK [node : Get the list of installed kernels] ********************************
    qemu: changed: [default]
    qemu:
    qemu: TASK [node : Get the current running kernel] ***********************************
    qemu: changed: [default]
    qemu:
    qemu: TASK [node : Set the number of kernels to keep] ********************************
    qemu: ok: [default]
    qemu:
    qemu: TASK [node : Filter out the current kernels] ***********************************
    qemu: ok: [default]
    qemu:
    qemu: TASK [node : Remove old kernels] ***********************************************
    qemu: ok: [default] => (item=['4.18.0-372.9.1.el8'])

/hold

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[vignesh-goutham]

/unhold

[abhay-krishna]

/approve

[eks-distro-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: abhay-krishna

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [abhay-krishna]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment