Refactor: Simplify progress indicator

Reduce & simlpify.

Cut feature: where we only report file count, it is always
useful to see file size as well.

cut feature: plural of file. If dust has only indexed a single file by
the time it prints the status then something has gone wrong, safe to
always assume a plural.

src/main.rs

@@ -179,7 +179,6 @@ fn main() {
         None
     } else {
         let conf = PConfig {
-            file_count_only: by_filecount, // recommend rm this
             use_iso: iso,
             ignore_hidden, // can we rm this?
         };