feat(engine): Refactor engine to support modular templates

[linuxluigi]

This PR introduces changes to the template engine to allow modular templates. A new module interface has been added, making it possible to create template modules in a separate git repository or folder, or even a custom binary. This allows users to create custom combinations of modules or add their own to the existing ones.

In addition, a new View interface has been added to allow for custom implementations. An example implementation has been included using the https://github.com/charmbracelet/bubbletea library.

Please note that this is a draft, and more changes will be required before this can be merged. Feedback and suggestions are welcome!