Use pyproject.toml for dependency management and tool configuration

[devsjc]

There are many files in the root of this repo dedicated to configuring tools. Since PEP-621, a pyproject.toml file has become the standard for managing python projects. As such, moving what configuration files can be moved into a pyproject file, along with the dependencies and project metadata, would keep PVNet up to date with recommended packaging practices. This will also require a modification to the github actions to work with the new file in releasing.

For more details on how to consolidate configuration into pyproject, see this blog post.