Add py2qasm CLI tool to qlasskit

[tomv42]

Description

This pull request introduces the py2qasm CLI tool to the qlasskit/tools package. The tool is designed to convert Python scripts containing qlassf functions into QASM code. Key features include:

• Input Handling: Reads from a specified input file or from stdin.
• Entrypoint Specification: Allows users to specify a function as the entrypoint for conversion.
• Output Handling: Outputs the result to a specified file or to stdout.
• Compiler Options: Supports both internal and tweedledum compilers.
• QASM Versions: Provides options for generating QASM code in versions 2.0 and 3.0.
• Version and Help Commands: Includes -v/--version to display the qlasskit version and -h/--help for usage instructions.

Changes Made

• Implemented the main functionality of the py2qasm tool in qlasskit/tools/py2qasm.py.
• Utilized argparse for command-line argument parsing.
• Added utility functions for reading input, converting to QASM, and outputting results.
• Included test cases in test_tools.py to ensure correct behavior.
• Updated setup.py to register the py2qasm entry point.

Test Cases

The following test cases have been added to test_tools.py:

• Test for version display.
• Test for output to stdout.
• Test for specifying an entrypoint function.
• Test for output to a file.
• Test for reading input from stdin.
• Test for generating QASM version 2.0 and 3.0 code.

Related Issues

This PR addresses issue #26

[tomv42]

@dakk Sorry for the commit duplication, I didn't branch from the right commit...