FFI transfer ownership instead of cloning

[mversic]

Inside ffi/derive/src/arg.rs when receiving input parameters to functions, every opaque structure is cloned so as not to deal with ownership transfer. In FFI calls best practice dictates that memory should be deallocated on the side of the FFI that allocated it. Cloning doesn't seem optimal and, if possible, some form of ownership transfer should replace it

[mversic]

Considering that opaque pointers are always allocated on the Rust side of the FFI their ownership can be sent back over and deallocated. But care must be taken to not transfer ownership of other structs

[mversic]

Ownership of opaque structs will be shared across FFI boundary after #2314 is merged