SMT input Python files are not valid Python 
The only valid input Python test case files for the SMT transpiler are

- https://github.com/py2many/py2many/blob/main/tests/cases/datatypes.py
- https://github.com/py2many/py2many/blob/main/tests/cases/demorgan.py
- https://github.com/py2many/py2many/blob/main/tests/cases/equations.py
- https://github.com/py2many/py2many/blob/main/tests/cases/smt_types.py

None of these files do anything useful in Python, and are all invalid test cases for all of the other transpilers.

I have attempted to make them valid Python files, and mostly succeeded, in https://github.com/py2many/py2many/pull/513 , which makes them use https://github.com/jayvdb/smtfe , but that project is a long way from being useful, and I am no longer using Python enough to make it worthwhile me pursuing alone.

As a result, I suggest that we repurpose the SMT transpiler as an example of how to create a transpiler using the new `py2many.registry` system.

i.e. pysmt would not be part of the `py2many` installed package.  Instead it would be revised slightly to be a separate non-published package that uses `py2many` as a library.  It would be removed from test_cli and test_unsupported.  I am happy to create a new the test system for it so it doesnt regress, and that CI would only run when there are changes to its special inputs or its code.