[Improvement] Iceberg REST server supports dynamic config for metalake

[liangyouze]

What would you like to be improved?

Currently, IRCS can automatically proxy a Gravitino Iceberg catalog under a metalake, but the metalake config is static, which means that every time a new metalake is created, a new IRCS needs to be started. I think the metalake config should also be dynamically fetched from Gravitino

How should we improve?

No response