Improving `Terminal` implementation

[cnpryer]

Summary

Implement more intentional usage of the Terminal abstraction for more cohesive Cargo UI. This would use Cargo's simple terminal messaging style for Huck-specific messages.

Motivation

• More consistent and polished experience
• Allows for better UI management during various ops
• Allows for animation and more frequent feedback

Requirements

• Simple
• Cargo's style
• Animation
• Snappy, minimal

Related:

• Logging and error-handling design #318
• Canceling child processes on Windows #790
• Printing to stdout #692
• (cargo) feat(help): Add styling to help output  rust-lang/cargo#12578