Ruby implement memsize functions for native types (#10291)

Fix: https://github.com/protocolbuffers/protobuf/issues/10280

This allows Ruby to report a more correct estimation of the memory used by these objects.

It's useful when running memory profilers against applications.

cc @zhangskz @haberman

Closes #10291

COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/10291 from casperisfine:ruby-sizes 9150795328267e69a0b8e241dda675402e5633e2
PiperOrigin-RevId: 606718632