Fix chains secret getting overwritten on upgrade

[piyush-garg]

This will fix chains' secret getting overwritten over upgrade

Now the secret has been moved out to a separate installerset and
this installerset will not be removed and changed over upgrade.

This installlerset will only be deleted if the namespace
of the tektonchains gets changed.

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Release Notes

Fix chains secret getting overwritten on upgrade

[concaf]

/hold
testing this locally

[sm43]

LGTM

[piyush-garg]

In this scenario, I did not choose the approach of applying secret directly without installerset and keeping the ChainsCR as owner, because in the case of chain CR is edited to install in a different namespace, we need to handle explicitly the case of secret deletion etc. So to achieve that, created a secret in a separate installerset and this installerset will be deleted only on the change of namespace for now else not, and removing chains will also delete the secret.

[concaf]

/hold cancel
/approve
/lgtm

[concaf]

/approve

[tekton-robot]

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