js: Show status for all log files

[perguth]

With some update to the backend code we can display the status of all log files in the log file overview on the left.

[ThomasWaldmann]

https://github.com/borgbackup/borgweb/commit/4992466d61e496df129ce4d596f90df781d26eed

With this changeset, it usually only reads 1 disk sector for each log file, so I think we can afford now classifying a lot more log files.

Using some sane upper limit for the classified log file count maybe still makes sense, we don't know how many log files people accumulate.