store addfile.logs in /STORE/logs dir outside collection repos

Instead of littering collection repos with addfile.log files
that slow down git-status whenever that is run, keep them all in
a log/ dir in the STORE.
tool for moving addfile.log files out of collection repos

This copies or moves all the addfile.log files out of a collection
into the /STORE/log dir and tars them up.
make dir for addfile log in log path func

Check for directory existence in the function that returns the
path rather than in the code that calls the function (so we don't
have to check for dir in multiple places).
Merge branch 'addfile-cleaner'