use air for consistent formatting and styling

[mrcaseb]

We should use air to consistently format R code.

Here are the steps:

• Configure project to use_air
• Format the complete project in a single squashed commit
• setup git to ignore that commit in git blame
• Add gha workflow to get automated formatting suggestions in PRs so PR authors don't necessarily need to run air locally.
• optionally setup RStudio or VS Code / Positron to format on save. It makes sense to do this but it's not required with the automated formatting changes in the above mentioned gha workflow

I think this is just state of the art and I would consider it good practice.