Put multiple frame md5sums into a single file
When enabled, the framewriters will write a md5sum file for each frame file. LDAS can consume these files to streamline how quickly data makes its way into the LDAS filesystem.
Unfortunately, writing a separate md5 file for each frame file creates lots of small files, which can be very inefficient on these QFS filesystems. Instead, we should be write a single md5sum file per frame directory. This would give us app. 1170 checksums per file instead of 1.