More efficient listing of files.
Listing files for the Change reporting used `p4 files //…@=<id>`, this now uses `p4 describe -s <id>` for changes and `p4 files //…@<id>` for labels.
The `\\…@label` should be much more efficient as it only looks as the db.label table not db.rev. I can’t limit the scope to a workspace. Often the client name uses ${var}, which are not present at this point in the code.