This helps to keep the prelude small and less likely to conflict with
other crates.
- remove widgets module from prelude as the entire module can be just as
easily imported with `use ratatui::widgets::*;`
- move prelude module into its own file
- update examples to import widgets module instead of just prelude
- added several modules to prelude to make it possible to qualify
imports that collide with other types that have similar names
- Reformat summary info
- Add badges for dependencies, discord, license
- point existing badges to shields.io
- add Table of Contents
- tweaked installation instructions to show instructions for new and
existing crates
- moved fork status lower
- chop lines generally to 100 limit
- add a quickstart based on a simplified hello_world example
- added / updated some internal links to point locally
- removed some details to simplify the readme (e.g. tick-rate)
- reordered widgets and pointed these at the widget docs
- adds a hello_world example that has just the absolute basic code
necessary to run a ratatui app. This includes some comments that help
guide the user towards other approaches and considerations for a real
world app.