[FeatureRequest] Rewrite the Dev Env Settings Window

[janosmurai]

Is your feature request related to a problem? Please describe.
The Dev Env Settings Window utilizes the rich library to create UI elements. These UI elements are implemented in the menu.py file. It's tedious and redundant to implement these components because other Python libraries already provide them.

Describe the solution you'd like
Rewrite the Dev Env Settings Window using Textual. Textual provides textual UI elements.
Everything should look and work the same as now, so the current UI can be used as a reference for validation.

This is how the Dev Env Settings Window looks like:

Easiest way to reach this UI is by the dem create command.

The functionality of the window should remain the same, but the sizes of the upper two panels should change. In v0.6.x the upper two panels dynamically changed with the number of items included in them. For the new layout, these two panels should always take all the available sizes regardless of the number of items listed in them.

Describe alternatives you've considered
Alternative libraries might also be used instead of Textual, but please let's discuss your recommendation before you jump into the implementation.

Additional context
The two affected files: menu.py and dev_env_settings_window.py

---

For axem internal use only:
Jira: https://axem.atlassian.net/browse/DEM-267