Revert "rm pyproject.toml, mv contents to setup.py" (#943)

This reverts commit 0fa3bbe5.

This resolves #943 (closed).

cmake/multipython/MakePythonWheel.cmake

@@ -46,6 +46,7 @@ set(_setup_py ${PY_OUTPUT_DIR}/setup.py)
 
 configure_file(${WHEEL_ROOT_DIR}/setup.cfg.in ${_setup_cfg} @ONLY)
 configure_file(${WHEEL_ROOT_DIR}/setup.py.in ${_setup_py} @ONLY)
+configure_file(${WHEEL_ROOT_DIR}/pyproject.toml ${PY_OUTPUT_DIR} COPYONLY)
 
 # copy text files