Support clone that lets you configure what parts of a `Program` to copy.

[MarquessV]

pyQuil's Program has a copy_everything_except_instructions method, which makes sense if you know the structure of that Program class, but can also be confusing since everything in a Quil program can be considered an instruction. Mirroring this method exactly in quil-rs would be even more misleading, since all the properties of quil-rs make up the instructions you get when calling the to_instructions() method. quil-rs also doesn't separate things into the same buckets as pyQuil, for example, DEFGATEs get lumped into body instructions, but pyQuil maintains a separate property for them.

Going back to pyQuil's copy_everything_except_instructions method, it turns out that the primary utility of this method has been to separate Quil-T instructions from Quil instructions. However, there are other edge cases where getting just things like DEFGATEs is also helpful. Instead of trying to account for all these edge cases, it seems better to create an easy way to copy a program, but only with instructions matching a certain criteria. This is already theoretically possible by just iterating over a program with to_instructions and using match statements to only collect certain types of instructions. Maybe this is the best way to do it, but since copying a program seems like a helpful utility, but since we already are providing methods of this nature (clone_without_body_instructions), maybe we can offer a method with a builder or some other type that lets you configure what to clone. This would provide a consistent way of creating clones of programs with specific sets of instructions to reduce repetition in our repo as well as boilerplate in downstream code.