Add verbose option

[ryuheechul]

Amber gives a lot of option to ignore things for different use cases which is great.
However it also comes with cost that there is a high chance that amber will run differently on different environments. And that could become hard to debug what things are being ignored and why.

In my use case is that running amber on Github Actions and somehow the target files being ignored and I just can't find why and the nature of Github Actions makes it hard to debug. Which is not a scope for Amber of course but I think having verbose option to see what amber is processing and skipping or ignoring and why would be awesome nonetheless.

[dalance]

I've added --verbose option.

[ryuheechul]

Fantastic, thanks!