Read config variable from mgmt cluster into cleanup cluster when deleting mgmt cluster

[ydp]

What this PR does / why we need it

When deleting management cluster, fetch tkg-tkp-tkg-system-values from mgmt cluster and configure it onto the cleanup cluster before install management packages.

Which issue(s) this PR fixes

Fixes #3420

Describe testing done for PR

Release note

Additional information

Special notes for your reviewer

[github-actions]

Hi @ydp! And thank you for opening your first Pull Request. Someone will review it soon. Thank you for committing to making Tanzu Framework better.

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3395/20220921015137/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[codecov]

Codecov Report

Merging #3395 (ac80da0) into main (ed3014a) will increase coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #3395      +/-   ##
==========================================
+ Coverage   54.21%   54.25%   +0.03%     
==========================================
  Files         107      107              
  Lines       10781    10781              
==========================================
+ Hits         5845     5849       +4     
+ Misses       4467     4463       -4     
  Partials      469      469              

Impacted Files	Coverage Δ
...ons/controllers/packageinstallstatus_controller.go	77.99% <0.00%> (-1.16%)	⬇️
addons/controllers/clusterbootstrap_controller.go	63.52% <0.00%> (+0.59%)	⬆️

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[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3395/20220922031422/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[wjun]

LGTM