Holesky testnet sunset

[m4sterbunny]

Due to https://blog.ethereum.org/2025/09/01/holesky-shutdown-announcement it will be a good idea to remove the links provided on https://docs.ens.domains/learn/deployments#holesky

[m4sterbunny]

Created PR #471, based on pr feedback, converted that to draft and will issue temp status pr just with warning instead

[m4sterbunny]

Created PR #476 as the first step to sunsetting Holesky