split pack-files.py into twi script

instead of only one script that handles both, filling the db
with the files metadata and creating the archives, the script
is split up into the scripts fillmetadata.py and pack-files.py.
fillmetadata.py runs in an infinite loop checking the db for
new files and pack-files.py runs an infinite loop collecting
"known" files and packing them.
extend infinite loops

the central infinite loops in fillmetadata.pz and pack-files.py are now
extended to also contain the loading and parsing of the configuration to
be able to dynamically pick up changes.
split bfid writing into writebfids.py script
improve signal handling

sigint does now not cause an immediate interrupt, but to stop the
script at the next most appropriate loop run. This allows to finish
"atomic" operations.
avoid using tail to parse the output of datasetPut.js is hsm-internal.sh

tail -n +2 was used to extract the data from the response of mongo.
Using "var" avoid the extra output and allows to use the output without
modifying it using "tail".