First attempt at logging cleanup. [1689]

This will attempt to rename “${mcv.userpath}/logs” to
“${mcv.userpath}/archived_logs”! This commit implements most of what
Inquiry 1689 recommends, but rather than deleting any files, it
currently just prints debug about the files that would’ve been removed.

I’ve tried to minimize the performance impact of the cleanup, but
anyone on a non-SSD drive may notice a hit. If that happens, *please*
let me know.