Add option to output file with installer hashes

[marcoesters]

Description

Add option to output hashes of installer file. The file format is written in a way that it can be verified with shasum -c and similar UNIX tools.

In order to work with installer_type: all (see issue #814), I merged the info objects before creating outputs. I'm not sure if that closes the issue, but it's a temporary workaround.

Checklist - did you ...

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?

[jaimergp]

LGTM but I wonder if the output files should be one per installer, named as {installer-name}-{version}.{extension}.{algorithm}; e.g. for Miniconda-24.5.0_py310.sh we would find SHA256 in Miniconda-24.5.0_py310.sh.sha256. I'm thinking of these files published next to the installers in Miniforge, for example.

[marcoesters]

LGTM but I wonder if the output files should be one per installer, named as {installer-name}-{version}.{extension}.{algorithm}; e.g. for Miniconda-24.5.0_py310.sh we would find SHA256 in Miniconda-24.5.0_py310.sh.sha256. I'm thinking of these files published next to the installers in Miniforge, for example.

I think that makes sense since users will download only one installer and then shasum -c would fail. I used the entire filename for simplicity though, which Miniforge does as well.