Refactor UI to use structured output util

[waynexia]

Describe This Problem

Currently sqlness outputs everything with println!. This is hard to maintain.

Proposal

Consider a structured way to organize our outputs. Either using existing util like TestReporter from nextest or wrap our own.

Additional Context

No response

[jiacai2050]

Any user case to collect stdout output?

[waynexia]

Any user case to collect stdout output?

No for now, just for refactoring

[jiacai2050]

Then I suggest we could define a trait to collect those info

trait Collector {
  fn append(&self, &str) -> Result<()>
  fn flush(&self) -> Result<()>
}

[waynexia]

Not sure if these are enough. This collector may also be exposed to users to replace their println in their sqlness runner