Make this package a package

[lysogeny]

These changes turn this package into a package.

To do this:

• Addea pyproject.toml that specifies dependencies, build system and other package medata.
• Move the main module source to src/resolve_tools
• Add __init__.py files
• Change the name of the module to snake_case
• Include a github actions workflow to build the package and display the build status badge.

These changes make this easily installable via pip:

pip install git+https://github.com/lysogeny/ResolveTools # update if merged

Note: You should probably change the URI of the badge to this repository if you pull it.