bindings: rust: allow cloning line::InfoRef -> line::Info

bindings: rust: allow cloning line::InfoRef -> line::Info

While one would usually use the ToOwned [1] contract in rust, libgpipd's
API only allows copying that may fail.

Thus, we cannot implement the existing trait and roll our own method. I
went with `try_clone` since that seems to be used in similar cases across
the `std` crate [2].

It also closes the gap of not having any way to clone owned instances.
Though - again - not through the Clone trait which may not fail [3].

[1] https://doc.rust-lang.org/std/borrow/trait.ToOwned.html
[2] https://doc.rust-lang.org/std/index.html?search=try_clone
[3] https://doc.rust-lang.org/std/clone/trait.Clone.html

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Erik Schilling <erik.schilling@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>