Rewrite GUI in a modern framework

[Era-Dorta]

TKinter is a very old framework, it looks bad and it's not great to code with.

Two modern libraries are

• https://github.com/hoffstadt/DearPyGui
• https://github.com/kivy/kivy

However, I'm more inclined to do it on the web, as we could run it on a docker container:

• https://github.com/gradio-app/gradio
• https://github.com/zauberzeug/nicegui/
• https://github.com/plotly/dash

Not sure which of these would be better. An open problem with running on the web is that we cannot have a local file picker. We can only upload files to the app. This can be partly circumvented by only processing files in a fixed folder.