[Task] Create Domain Linkage credentials in tooling generation step

During creation of the issuer identities we need to also create the domain linkage credentials for each issuer for a distinct domain each.
We can use the issuer name/identifier for the sub-domain like `cargo run --release -- selv.iota.org bank government insurance` leads to a credential being created for `bank.selv.iota.org` for the bank issuer and so on.