Improvements to cabal make targets

[pcapriotti]

• Speed up installation by using parallel xargs
• Allow package=all to act on all packages

Checklist

• The PR Title explains the impact of the change.
• The PR description provides context as to why the change should occur and what the code contributes to that effect. This could also be a link to a JIRA ticket or a Github issue, if there is one.
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  • A file with the changelog entry in one or more suitable sub-sections. The sub-sections are marked by directories inside changelog.d.