[MATLAB] Create utility functions for simplifying management of `Proxy` instances for `Array`s

[kevingurney]

Describe the enhancement requested

This is a follow up to https://github.com/apache/arrow/pull/38357#discussion_r1365908049.

In the C++ code for the MATLAB interface, we frequently wrap/unwrap Arrow types, like arrow::Array, into/from a corresponding libmexclass Proxy objects. This currently takes several lines of code, leading to lots of code duplication and introduces room for subtle implementation errors.

It would be helpful to abstract away some of the steps involved in Proxy creation/management into a set of helper utilities that we can reuse in the C++ code for the MATLAB interface.

Component(s)

MATLAB