[FEATURE] Supports GoogleAuthenticator in the server

### Describe the feature

Iceberg client RESTCatalog has supported
https://github.com/apache/iceberg/blob/main/gcp/src/main/java/org/apache/iceberg/gcp/auth/GoogleAuthManager.java

Gravitino Iceberg REST catalog should extract the principal from and validate the token

### Motivation

Fill the gaps between Iceberg implementation and strengthen the ecosystem.

### Describe the solution

_No response_

### Additional context

_No response_

Start by reading Iceberg's gcp/src/main/java/org/apache/iceberg/gcp/auth/GoogleAuthManager.java and tracing the RESTCatalog authentication flow. Then locate Gravitino's Iceberg REST catalog token handling; done means extracting the principal and validating the token consistently with the Iceberg implementation.

Written by the indexing model from the issue text.