Pull out the metrics suffixes to a static constant.
Pull out the metrics suffixes to a static constant.

Yossi asked us to do this for RQC in a different PR.

broadinstitute/picard,broadinstitute/picard,nh13/picard,annkupi/picard,alecw/picard,broadinstitute/picard,alecw/picard,nh13/picard,nh13/picard,annkupi/picard,broadinstitute/picard,annkupi/picard,annkupi/picard,alecw/picard,broadinstitute/picard,alecw/picard,nh13/picard