calculate checksums for the produced files

[b97pla]

• the end result files from the pipeline (e.g. bars, vcfs) should be checksummed and the checksum written to a file with the same name as the checksummed file and with a file extension indicating the checksum algorithm, e.g. the-final-bam-file.bam --> the-final-bam-file.bam.md5
• the checksum should be written on the first line of the file followed by a newline or EOF

[b97pla]

won't have