Is your feature request related to a problem? Please describe.

After updating protobuf schema, we can set the is_remote_parent flag when exporting spans and span links with OTLP.

Describe the solution you'd like

Update OTLP exporter to fill the relevant bits in SpanFlags.

Describe alternatives you've considered

None

Additional context

Proto schema PR: open-telemetry/opentelemetry-proto#484
Go implementation: https://github.com/open-telemetry/opentelemetry-go/pull/5194/files
Python implementation: https://github.com/open-telemetry/opentelemetry-python/pull/3881/files