refactoring with desperado

[xoolive]

@abc8747 Could you please confirm the following commands work for you when you have coverage?

cargo run --release --features rtlsdr -- rtlsdr:// --redis-url redis://localhost:6379
cargo run --release --features soapy -- soapy://driver=rtlsdr --redis-url redis://localhost:6379

[abc8747]

Confirmed works well on both rtlsdr:// and soapy://

Maybe in the future we could have some way to control gain in AisIqSource::from_rtlsdr and the CLI