[konflux] allow field to override konflux template url

[ashwindasr]

Since we are now dynamically pulling the PipelineRun template from https://github.com/openshift-priv/art-konflux-template/blob/main/.tekton/art-konflux-template-push.yaml, in case if there is an issue with one of the newer task builds, having this option will allow us to use a temporary roll back if necessary, instead of merging a revert PR, thereby offering us more flexibility.

Alongside openshift-eng/aos-cd-jobs#4313

[openshift-ci]

@ashwindasr: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/security	20ffa6a	link	false	/test security

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[vfreex]

/lgtm
/approve

[openshift-ci]

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