This allows the use of custom 'envelope' types like ActionResult<> with
a corresponding API Explorer implementation.
Basically this PR services to decouple a bunch of infrastructure from
ActionResult<>.
- #7413 part 1 of 2
- made all `ModelMetadataProvider` and `ObjectModelValidator`-specific code conditional
- fortunately, `MvcOptions` easy to get; affected code is primarily `internal` or pub-`Internal`
- remove unnecessary `ModelMetadataProvider` use in `ApiBehaviorApplicationModelProvider`
- run integration and functional tests with `CompatibilityVersion.Version_2_1`
- functional test change depends on @javiercn's recent #7541 fix
- remove test code now redundantly turning compatibility switches on
nits:
- correct spelling errors in `CompatibilitySwitch`
- take VS suggestions, mostly in test code
- rename methods in `ControllerBinderDelegateProviderTest` to match current API
- slightly refactor in `ApiBehaviorApplicationModelProvider`
- #7044
- move `IHttpResponseStreamWriterFactory` too
- add breaking change records e.g. for changes to `BodyModelBinder[Provider]` constructors
- these changes relate to previously-"internal" constructors and one property
nits: take VS suggestions for changed files
Ryan Nowak
Doug Bunting
Kiran Challa
Pranav K
Steve Sanderson
Ryan Brandenburg
Jass Bagga
Ajay Bhargav Baaskaran