Interactive Usage Bar Granularity about dua-cli

[vks]

It probably makes sense to use https://github.com/mitsuhiko/indicatif in the long term for this and progress reporting.

indicatif would also be my choice, but it would certainly be interesting to get a look at the version that @LovecraftianHorror created to get a better idea of what they mean.

Just some notes about the current implementation.

• when scanning the disk, there is a rate-limited update every few milliseconds, but due to the way it works the actual entry (the one with the percentage and bar) updates much more rarely. Numbers take time to bubble up.
• When deleting entries, it will only send an update after each entry in the list was deleted. If big folders are deleted, there is no much to see for a while. This is something that could certainly benefit a lot from enhancements.

[CosmicHorrorDev]

82333ac and 26b9569 add this functionality