CLI that shows the contents of a TRX

[arokem]

I.e. a call on my_file.trx would list what groups and what dpg/dps are stored in the file.

Could be a variation on https://stackoverflow.com/a/57922972/3532933

[mattcieslak]

Users will most likely want to know what's in a trx file before opening a python session, unzipping the trx or looking up how to list zip file contents. I was thinking it could be nice to have a command line tool that prints the contents of a trx file