Create MD5s for All Existing Binaries

[CodeGat]

Background

After #340, we still need to add MD5 hashes to all existing binaries for each spack instance on Gadi.

Furthermore, we need to add this data to the Release Database, once https://github.com/ACCESS-NRI/tracking-services/issues/84 is merged.

[CodeGat]

Note: I've now gone through all the binaries for the important package in our Release instances of spack v[0.20|0.22], and adding the md5sum to them as a BINARY.md5 file.