Update SWIG used to generate the Matlab bindings to SWIG 4

[traversaro]

We have been using our own fork of SWIG to generate the MATLAB bindings from https://github.com/robotology-dependencies/swig for some time, but now upstream SWIG has been updated, and it would be great to use a SWIG fork with MATLAB support based on SWIG 4.

The fork at https://github.com/Alzathar/swig seems to be a good candidate (see the related PR: swig/swig#1519), as it is based on SWIG 4 and it seems to do not include the PR jaeandersson/swig#92 that created problems to us in the past.

Looking at the commit that we have in https://github.com/robotology-dependencies/swig, we should check if the fix robotology-dependencies/swig#2 need to be ported on the top of the new SWIG 4 with MATLAB support, or it is not necessary anymore. Probably running the iDynTree testsuite is sufficient.

[traversaro]

cc @gabrielenava @fjandrad @nunoguedelha

[traversaro]

Actually now a good candidate seems KrisThielemans/swig@f606f53, from jaeandersson/swig#96 .

This should permit use to use the std::shared_ptr support without excluding it in MATLAB, see #1037 .

[traversaro]

Actually now a good candidate seems KrisThielemans/swig@f606f53, from jaeandersson/swig#96 .

This should permit use to use the std::shared_ptr support without excluding it in MATLAB, see #1037 .

Actually this is not true, as the shared_ptr support is missing in the matlab directory even in that commit.