[Go SDK] Add flag for Dataflow Service Options to dataflow runner

This would allow the Go SDK to use dataflow service options for environment configuration

eg. for enabling secure container boot:
https://cloud.google.com/dataflow/docs/guides/deploying-a-pipeline#python_12

They eventually get plumbed to here: https://pkg.go.dev/google.golang.org/api/dataflow/v1b3#Environment

Ultimately, needs to be plumbed to the Environment.ServiceOptions field somewhere here:
https://github.com/apache/beam/blob/716e3b1ddce527d6a10d054e55da55d80ebe8513/sdks/go/pkg/beam/runners/dataflow/dataflowlib/job.go#L157

Simple enough: Add a flag that accepts a comma separated list of options, parse those to a []string, and populate

Flag would go here: https://github.com/apache/beam/blob/716e3b1ddce527d6a10d054e55da55d80ebe8513/sdks/go/pkg/beam/runners/dataflow/dataflow.go#L53