Task for job interview.
rust >= 1.36
cargo run --release
Program saves expected values to file output.csv, with data from files input.csv, hotels.json, room_names.csv.
Program loads only key data from files hotels.json and room_names.csv in to BTreeMap with the value pointing to start of line in file.
File names of all files are hardcoded in src file: src/consts.rs.