Dfvue

* Back to pack layout manager for resizing of plotting window.
* pyplot was not imported on Windows in `dfvue`.
* `Transform` window to manipulate DataFrame.
* Correct datetime formatting in coordinate printing.
* Move from token to trusted publisher on PyPI.
* Silence FutureWarning from `pandas.read_csv`.

* Allow multiple input files that will be concatenated.

* Use Azure theme if CustomTkinter is not installed such as in
conda environments.
* Increased size of ReadCSV window to fit widgets on Windows.

* Exclusively use CustomTkinter.
* Updated documentation with new screenshots.

* Using CustomTkinter on top of Tkinter.
* Use mix of grid and pack layout managers.

* Works with newer and older matplotlib versions.