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ARROW-15650: [MATLAB] Rename the MEX gateway function

## Overview
The MATLAB Interface to Arrow contains a [MEX](https://mathworks.com/help/matlab/call-mex-files-1.html?s_tid=CRUX_lftnav) function named `mexfcn` to delegate MATLAB calls to C++ functions that implement the functionality.

When the interface is installed, the name of the MEX function, `mexfcn`, is on the global [MATLAB Search Path](https://mathworks.com/help/matlab/matlab_env/what-is-the-matlab-search-path.html). Because the previous name only captured that it is related to MEX functionality, it may cause conflicts with functions outside of the MATLAB Interface to Arrow.

## Implementation
The following changes were made to address the potential naming conflict:
- Rename the MEX function to `call`.
    - The name of the MEX file will be: `call.<mex-extension>`
- Install the MEX function to the MATLAB package folder hierarchy: `+arrow/+cpp` within the installation directory.
    - Within MATLAB, the function is accessed by the following function signature: `arrow.cpp.call('<cpp-function-name>', <cpp-function-argument-1>, ..., <cpp-function-argument-N>)`.
- Install all dependencies of the MEX function to the same package folder hierarchy.
- Updated MATLAB tests to use the new function name.

## Testing
- The change was qualified locally on Windows 10 (Ninja and Visual Studio), macOS 11.5 (Ninja and Xcode) for the following configurations:
    - Build both Arrow and GTest.
    - Use `ARROW_HOME` and `GTEST_ROOT`.
- Additionally, the GitHub Actions CI passed for the change on Linux and macOS.

## Notes
Thank you for working on this pull request with me, @kevingurney!

Closes #12424 from lafiona/ARROW-15650

Lead-authored-by: Fiona La <fionala@mathworks.com>
Co-authored-by: Kevin Gurney <kgurney@mathworks.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>