Change all AlchemiscaleClient methods to use retrieve_* instead of get_* if they return GufeTokenizables

[dotsdl]

It's currently the case that the AlchemiscaleClient has many get_* methods that either return ScopedKeys, GufeTokenizables, lists or dicts of these, or primitive types (such as ints for weights). However, those methods that return GufeTokenizables are often slower due to the higher complexity of these objects, and these objects often cannot be used to refer to other objects in the server, as ScopedKeys can.

To distinguish methods that return GufeTokenizables from those that do not, we propose changing all such methods to start with retrieve_* instead of get_*.

This will enable us to distinguish between methods like get_task_results that should give ScopedKeys for ProtocolDAGResultRefs, and retrieve_task_results, which should return ProtocolDAGResults. The former method could be used for further introspection, such as retrieving execution logs, provenance, STDERR, STDOUT, or result files, while the latter would yield the result objects themselves.