Deprecated the following args and their call sites
- runtime_type => dagster_type in StepInput and StepOutput
- runtime_type => dagster_type in IntermediateStore.[set|get]_[object|value]
^ Most IntermediateStore.[set/get]_[object/value] are called without argument names. So I decided to rename it without keeping the old name, as there may be fewer breaking changes when just renaming the arg.