Add renovate configuration

[pmalek]

Problem statement

Other repos managed by Kubernetes team already have renovate configured (e.g. KGO https://github.com/Kong/gateway-operator/blob/main/renovate.json and KIC https://github.com/Kong/kubernetes-ingress-controller/blob/main/renovate.json)

This issue tracks the effort of adding renovate configuration in this repo

Acceptance criteria

• Renovate is configured in ktf