remove DB

[c-cube]

just rely on self-contained JSON files, and a list of directories to search for those files. They should contain:

• the raw results
• a UUID (use uuidm with V4)
• a timestamp for the start time (and maybe finish time)
• maybe some other metadata ($USER, etc?)

[c-cube]

Search in several directories for stored json files:

• by default, ~/.frogutils/ (see xdg standards maybe?)
• command line arguments

Also, frogbench/frogtest should store their results in one of those directories