Migrate to poetry and pyproject.toml, adopt ruff and pre-commit, reorganize tests and CI, and update docs

[keithchev]

This PR includes a number of changes that were made in a private fork of readlif at Arcadia. In September 2024, Arcadia took over ownership of the public readlif repo from its original maintainer (Nick), allowing us to contribute these changes back to the public repo.

Tooling

• migrate the project to use poetry for dependency management and build tooling.
• migrate the package from setup.py to pyproject.toml.
• migrate the tests to pytest and reorganize test artifacts.
• update and reorganize the CI workflow into separate workflows for linting and testing.
• introduce ruff for formatting and linting.
• introduce pre-commit hooks.

New features

• add a convenience method to LifFile to get an image by name.
• add a method to return an image as a numpy array.
• add a method to parse laser powers from the XML metadata.

Other changes

• fix a bug in get_plane related to reading 16-bit images.
• move the changelog to its own file.
• add dev docs and update the main README.