[291] Nanobind for QueryAnswer and DASNode

[Pedrobc89]

closes #291

[angeloprobst]

@pedro-costa-techlabs const char* (or any other type of pointer) in nanobind is always challenging and should be avoided.

This particular case is even more complicated because handles is an array of pointers, so the binding implementation must translate it to a format that nanobind knows how to deal with, as follows:

#include <nanobind/stl/vector.h>
...
    .def_ro(
        "handles",
        [](const HandlesAnswer& self) -> const vector<string> {
            vector<string> handles;
            for(size_t i = 0; i < self.handles_size; i++) {
                handles.emplace_back(self.handles[i]);
            }
            return handles;
        })

[angeloprobst]

I think this could also require a special treatment for const char* handle:

    .def(
        "__init__",
        [](HandlesAnswer& self, const string& handle, double importance) {
            new (&self) HandlesAnswer(handle.c_str(), importance);
        },
        "handle"_a,
        "importance"_a)

[angeloprobst]

Suggested change

	.def(nb::init<string>(), "local_id"_a)
	.def(nb::init<const string&>(), "local_id"_a)

Please revisit the other functions/constructors to ensure that the binding is expecting/passing in the right types, including aspect modifiers like const, &, etc.