Add Immunarch workflow

[BrunoGrandePhD]

For Immunarch, this PR includes:

• CWL tool
  • JSON example input for both PCAWG and TCGA
• CWL Synapse workflow
  • Tested locally with personal Synapse credentials
• CWL checker workflow
  • JSON example scatters across the two examples (PCAWG and TCGA)

Additionally, I updated the md5sum_checker CWL tool to parameterize the status output file name. The default is what it used to be, so this change should be backwards-compatible. This way, there isn't a clash when running the checker workflow on PCAWG and TCGA in parallel.