Add Etherlink Shadownet Testnet (Chain ID: 127823)

[sistemico]

Network information
Network Name	Etherlink Shadownet Testnet
Chain ID	127823
RPC Endpoint	https://node.shadownet.etherlink.com
Block Explorer	https://shadownet.explorer.etherlink.com/

More info

[github-actions]

You successfully submitted a PR! Due to the amount of PRs coming in: we will only look at PRs that the CI is happy with. We can also not hold your hand getting the CI green - just look how others that where merged did it and RTFM. So as long as there is any CI check that reports an error - no human will look at this. You might be able to ask for some support after supporting the project - e.g. by sending funds to lists.eth. When you fixed things after a requested change - then you also need to (re-)request a review.

[skenaja]

This is a duplicate of #7796 (which also covers the sunsetting of Etherlink Ghostnet Testnet)

[Makhdoom710]

Network information
Network Name Etherlink Shadownet Testnet
Chain ID 127823
RPC Endpoint https://node.shadownet.etherlink.com
Block Explorer https://shadownet.explorer.etherlink.com/
More info

[Makhdoom710]

Mak