[feature] Adds a --filter option to `cmd` for pretty-printing.

The option accepts a message type and prints the values in the csv
format:
msgtype, time, payload if the --filter option is recognized
msgtype, time otherwise
The print is force-flushed on stdout.
This switches CI to the "refactored" CI identifier at argotests/tests
8 jobs for pretty-printing-cmd-listen in 2 minutes and 21 seconds (queued for 2 seconds)