Implement trait based API for defining AggregateUDF #8710

Similarly to #8568

Is your feature request related to a problem or challenge?

The current way a user implements a AggregateUDF is awkward and very hard to extend in backwards compatible ways:

They must wade through several Arc<dyn<...> typedefs to figure out how to provide the type signature and implementation

impl AggregateUDF {

/// Create a new AggregateUDF 
pub fn new(
    name: &str,
    signature: &Signature,
    return_type: &Arc<dyn Fn(&[DataType]) -> Result<Arc<DataType>, DataFusionError> + Send + Sync>,
    accumulator: &Arc<dyn Fn(&DataType) -> Result<Box<dyn Accumulator>, DataFusionError> + Send + Sync>,
    state_type: &Arc<dyn Fn(&DataType) -> Result<Arc<Vec<DataType>>, DataFusionError> + Send + Sync>
) -> AggregateUDF {
...
}

Describe the solution you'd like

Follow the pattern in #8578

1. Create a AggregateUDFImpl trait, and AggregateUDF::new_from_impl that creates an AggregateUDF from the impl
2. Add an example in datafusion-examples/examples/advanced_udaf.rs of using this API

I am not sure why this API is implemented like it is (other than it was consistent with ScalarUDF). As a user I would expect to be able to use a trait object like this

like

struct MyUDF { 
..
}

impl AggregateUDFImpl for MyUDF {
  fn name(&self) -> &str, 
  fn return_type(&self) -> &DataType, 
...
}

Describe alternatives you've considered

No response

Additional context