## Summary of the Pull Request
Adds support for vintage style opacity, on Windows 11+. The API we're using for this exists since the time immemorial, but there's a bug in XAML Islands that prevents it from working right until Windows 11 (which we're working on backporting).
Replaces the `acrylicOpacity` setting with `opacity`, which is a uint between 0 and 100 (inclusive), default to 100.
`useAcrylic` now controls whether acrylic is used or not. Setting an opacity < 100 with `"useAcrylic": false` will use vintage style opacity.
Mouse wheeling adjusts opacity. Whether acrylic is used or not is dependent upon `useAcrylic`.
`opacity` will stealthily default to 50 if `useAcrylic:true` is set.
## PR Checklist
* [x] Closes#603
* [x] I work here
* [x] Tests added/passed
* [x] https://github.com/MicrosoftDocs/terminal/pull/416
## Detailed Description of the Pull Request / Additional comments
Opacity was moved to AppearanceConfig. In the future, I have a mind to allow unfocused acrylic, so that'll be important then.
## Validation Steps Performed
_just look at it_
74f11b8203
