Support ROFL transactions

[anzoman]

When following the ROFL Quickstart from the docs using my web wallet, I noticed that all ROFL transactions are marked with a warning icon and a message saying Unrecognized transaction, method rofl.. This can be confusing for the users, as ROFL transactions are more newer thing that should be recognized by the wallet.

https://wallet.oasis.io/account/oasis1qrjcyxa8luk3f85xupyzal3xkasfxwkjrumn86kd testnet

It would be useful to drop the message and add a similar icon that is used in Oasis Explorer for ROFL transactions.