cleanup brs when brupop is removed from the node.

[gthao313]

Issue number: #107

Description of changes:

Author: Tianhao Geng <[email protected]>
Date:   Thu Aug 11 19:32:12 2022 +0000

    cleanup brs when the brupop is removed from the node

    Currently we require customers to manually clean up the Custom Resources
    if they choose to delete only the updater-interface-version label. This
    change would help on automatically cleaning up BRS if customer removes
    brupop(label) from corresponding node.

commit b81eefc195f4669510146793acf64b3c5bc959e9
Author: Tianhao Geng <[email protected]>
Date:   Thu Aug 11 18:36:49 2022 +0000

    Add deletion support to brs client

    According to brs cleanup strategy, we support brs client to be able to
    delete brs object.

Testing done: Method: Run brupop integration test. Remove brupop label from nodes, and then confirm if associated brs has been removed.

Test with three scenarios

• [x] [Waiting-for-update] The node is waiting for update and customers remove the labels
• [x] [In-progress] Customers remove the labels when brupop is preforming update on the node.
• [x] [Complete] The node has been updated, and customers remove the labels.

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.