[Feature Request]: Enhancement of Go's datastoreio package

### What would you like to happen?

I would like to enhance the functionality of [Go's datastoreio packege](https://pkg.go.dev/github.com/apache/beam/sdks/go/pkg/beam/io/datastoreio). In Python, there are flexible queries to the Datastore, as well as writing and deleting capabilities.
https://beam.apache.org/releases/pydoc/2.13.0/apache_beam.io.gcp.datastore.v1new.datastoreio.html

However, in Go's package, there is only Read, which reads all rows of a kind.
https://pkg.go.dev/github.com/apache/beam/sdks/go/pkg/beam/io/datastoreio

I would like to have the ability to perform flexible queries and write and delete operations in Go, just like in Python.

### Issue Priority

Priority: 3 (nice-to-have improvement)

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