This adds [`XamlStyler.Console`] to our solution, and calls it when we
format the code, to also format
our .xaml files.
* `XamlStyler.Console` is a dotnet tool so it needs to be restored with
`dotnet tool restore`
* I've added a set of rules to approximately follow [@cmaneu's XAML guidelines].
Those guidelines also recommend things based on the code-behind, which
this tool can't figure out, but also _don't matter that much_.
* There's an extra step to strip BOMs from the output, since Xaml Styler
adds a BOM by default. Some had them before and others didn't. BOMs
have been nothing but trouble though.
[`XamlStyler.Console`]: https://github.com/Xavalon/XamlStyler
[@cmaneu's XAML guidelines]: https://github.com/cmaneu/xaml-coding-guidelines
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