Add Swell (Testnet)

[atenjin]

Adding a New Chain

This PR adds Swell Testnet to the registry.

Checklist

• I have declared the chain at the appropriate Superchain Level.
• I have run just validate <chain-id> locally to ensure all local validation checks pass.
• I have run just codegen to ensure that the chainlist and other generated files are up-to-date and include my chain.

[sigma]

Looks like this doesn't apply cleanly to main anymore

• just codegen adds a "governed_by_optimism" flag
• just validate 1924 throws some errors:

=== RUN   TestValidation/Swellchain_Testnet_(1924)/Data_Availability_Type
    data-availability-type_test.go:56:
                Error Trace:   .../github.com/ethereum-optimism/superchain-registry/validation/data-availability-type_test.go:56
                                                        .../github.com/ethereum-optimism/superchain-registry/validation/validation_test.go:44
                Error:          Received unexpected error:
                                operation failed permanently after 3 attempts: failed to retrieve previous nonce: missing trie node 486e81dbaf0d082af8a24573c8588c9db1fe72046a2a50fc5938baf82a3a18d0 (path ) state 0x486e81dbaf0d082af8a24573c8588c9db1fe72046a2a50fc5938baf82a3a18d0 is not available
                Test:           TestValidation/Swellchain_Testnet_(1924)/Data_Availability_Type
                Messages:       failed when checking chain for recent batcher txs from 0x77C60EfDBDa83410EE0373Eda2ed06891238c93d
--- FAIL: TestValidation/Swellchain_Testnet_(1924)/Data_Availability_Type (3.97s)

[mslipper]

This PR is missing some key addresses from addresses.json like L1CrossDomainMessenger. Can you please add these addresses?

[Wazabie]

This PR is missing some key addresses from addresses.json like L1CrossDomainMessenger. Can you please add these addresses?

@atenjin please see the above