Add .JuliaFormatter.toml

[kylebeggs]

Not only would a consistent formatting across the repo help readability, but also in PRs/commit diffs so your eyes are not distracted by silly changes like adding a space or something

[termi-official]

Yea I also already thought about using this or Runic. Any recommendations here?

[kylebeggs]

I haven't used Runic, but I don't think it's that big of a deal to have different code repos have different styles. I think Julia's syntax is clean enough in general that any style is somewhat readable. The important thing is consistency, and most people use VSCode which comes with built-in support for JuliaFormatter where the user has to do nothing, so I think that is best. Probably best to just go with the sciml style since we interface/use the sciml ecosystem a lot.

[kylebeggs]

I'll add this and add a format check in the CI as well once #163 is merged.

[termi-official]

Sure. #144 is also waiting for 163 to not complicate things.