Provide SHA256 sums for downloads not just MD5
Downloads posted to https://octopus.com/downloads have MD5 sums available, but some tools use SHA256 to verfify downloads.
A specific example is discussed in this github issue: https://github.com/cvent/octopus-deploy-cookbook/issues/75
The workaround as mentioned is to download the binary, check the MD5 sum and then obtain the SHA256 sum on your own. While not difficult, it does introduce extra manual steps needed for each release.
Having access to Octopus provided SHA256 sum for each download would streamline the use of other automation tools like Chef to setup Octopus.
We currently expose the sha256 hash through the HTTP header through the MSI download link.
The header is `x-amz-meta-sha256` alongside the existing `x-amx-meta-md5`. Although this is not immediately provided through the portal this will provide the required information.
the HTTP headers
are both provided