Add RadiumBlock bootnode to Moonbeam spec

[radiumb]

What does it do?

Add RadiumBlock bootnode to Moonbeam spec

Is there something left for follow-up PRs?

No

What alternative implementations were considered?

None

Are there relevant PRs or issues in other repositories (Substrate, Polkadot, Frontier, Cumulus)?

None

What value does it bring to the blockchain users?

Have another bootnode to discover peers

[pLabarta]

Node is able to sync with both endpoints :heavy_check_mark:

[RomarQ]

The provided bootnodes seem to be offline.

Tested with the following command:

./moonbeam --chain=moonbeam --reserved-only --reserved-nodes /dns/moonbeam-bootnode.radiumblock.com/tcp/30333/p2p/12D3KooWMrR6TV7q1gQxMJ6B9jfU6V8tgxkzUZExYK9jfyZLa6U7 /dns/moonbeam-bootnode.radiumblock.com/tcp/30336/wss/p2p/12D3KooWMrR6TV7q1gQxMJ6B9jfU6V8tgxkzUZExYK9jfyZLa6U7

[radiumb]

We have fixed the issue with the bootnode and tested it.