Get app information in a straightforward way

[niku]

Summary of changes

It changes getting app information in a straightforward way. It makes a bit slower, but getting better readability.

Checklist

• [x] New functions have typespecs, changed functions were updated
• [x] Same for documentation, including moduledocs
• [x] Tests were added or updated to cover changes
• [x] Commits were squashed into a single coherent commit

Licensing/Copyright

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[philipgiuliani]

Hi, I just tried this change out in my own Makefile, I noticed some downsides when using this cleaner approach.

• The application needs to be compiled
• It will be compiled twice, once on the ci server/local machine, and once while building the Docker image.
• mix run -e '...' starts the application, which will in my case connect to the database.

[bitwalker]

The example in the docs is not necessarily totally flexible, but it is consistent with the example application it is used with; in general I prefer the faster option, and as you've found, it is quite easy to have the version be parsed however you like. While I appreciate the desire for a cleaner approach in the docs here, that particular piece is mostly a bonus feature for people to play with, and as pointed out by @philipgiuliani, there are some downsides.

I'm going to close this PR, but if the issue comes up again and there is some consensus around the best approach, I'm happy to make changes at that point. Thanks for the PR!