Remove Option wrappers for owned objects

[milyin]

Describe the feature

The Rust object is represented in zenoh-c's owned structure is one of the following ways:

• as Option. In this case gravestone state (state after drop) is none
• just as RustObject. Gravestone object is some empty state of the object.

It would be good to get rid of first representation by providing internal "gravestone" state to all rust objects used in zenoh-c.
This would allow to avoid potential crashes when zenoh-cpp attempts to perform "std::move" on some mutable property of rust object.

This is already implemented for some objects, like payload: the C and C++ code are allowed to "take" payload from mutable reference to payload, replacing existing payload with "empty" one (with null data pointer and zero size).

But if the e.g. Sample is available by mutable reference, we can't simply take it, because it's represented in C++ as Option<Sample> and we'll put value None to &mut Sample, which will cause crash.

At this moment the problem is solved by operation take_from_loaned which is implemented only for objects which needs this functionality (callback parameters) and replaces original Sample,Query,etc with empty one. This "empty" value is not a real "gravestone" state, i.e. it may require a drop. See PR #923

But the better solution proposed by @DenisBiryukov91 is to provide such "empty" states for all objects and make them "gravestone", i.e. use them in drop. This will improve code simplicity (no extra "Option" wrapper) and safety (when object is available by mutable reference, it's aways safe to take it, replacing with empty state)