This commit uses the embedded style struct for styling in all components. The most notable example is `gum write` where there are many styles that are used and composed for each component of the command.
Input provides a shell script interface for the text input bubble. It
can be used to prompt the user for some input. The text the user entered
will be sent to `stdout`.
```
gum input --placeholder "What's your Bubble Gum flavor?" > answer.text
````