k8s upgrade via Horizon - Add "to-version" field to k8s upgrade strategy

[Cristian Mondo]

Brief Description
-----------------
k8s upgrade via GUI - Add "to-version" field to k8s upgrade strategy

This option is available via cli but it is not available via GUI.

It would be good to have it in the following scenario:

    customer has a subcloud group with subclouds with different k8s versions
    custumer wants to sync k8s version for all subclouds using the highest active version among the subcloud.
        Using the field "to-version" it would be possible to use a specific kube version and the orchestration would skip the subclouds which already have the target kube version as an active version.
        if the field "to-version" is not specified the orchestration will upgrade all the subclouds to its available kube version, which can be different between each other.

Severity
--------
<Minor: System/Feature is usable with minor issue>

Steps to Reproduce
------------------
    deploy a dc system with multiple subclouds
    create a kube upgrade strategy on GUI
        select "subcloud-group" to "Apply to" field

Reproducibility
---------------
State if the issue is 100% reproducible

System Configuration
--------------------
Dc systems

Workaround
----------
Using CLI to upgrade instead of GUI

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/gui/+/859639

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/gui/+/859639
Committed: https://opendev.org/starlingx/gui/commit/e9998f2d0b0bd3b6bd3eb2fa6ea08fb744af2cc5
Submitter: "Zuul (22348)"
Branch: master

commit e9998f2d0b0bd3b6bd3eb2fa6ea08fb744af2cc5
Author: Cristian Mondo <email address hidden>
Date: Wed Sep 28 12:35:06 2022 -0300

    To-version field is missing for K8S upgrade strategy on GUI

    This change is to add the To-version GUI field for K8S upgrade strategy.
    Currently this field is only present as a parameter in the CLI.

    Closes-Bug: 1991129

    Test Plan:

    - Perform upgrades strategies from GUI and select specific Kube version.
    - If the version is not selected, it will be updated to the first
      version that is available.

    Signed-off-by: Cristian Mondo <email address hidden>
    Change-Id: Ib93f156624009e80a48bb861e773edc6c4269472