IRC Events Endpoint Implementation: Request & Response Objects

### Feature Request / Improvement

We have reached good consensus on the [IRC Events Endpoint](https://github.com/apache/iceberg/pull/12584). Before merging this new Endpoint to the REST Catalog Specification, we want to implement core classes.

This Issue is about implementing Request as Response objects from the proposal including serialization & deserialization tests. The objects to implement are especially `QueryEventsRequest` and `EventsResponse` including all depending objects such as `Event` and all `XXXOperation`.

### Query engine

None

### Willingness to contribute

- [ ] I can contribute this improvement/feature independently
- [ ] I would be willing to contribute this improvement/feature with guidance from the Iceberg community
- [ ] I cannot contribute this improvement/feature at this time

Start by reading the IRC Events Endpoint proposal linked from the issue, then inspect the existing REST Catalog request and response patterns. Implement QueryEventsRequest, EventsResponse, Event, and the dependent XXXOperation objects, with serialization and deserialization tests. Done means the proposal's request and response objects are represented and covered by those tests.

Written by the indexing model from the issue text.