Remove or make public pubternals for Http

[Tratcher]

#11312, #2979 Removes Microsoft.AspNetCore.Builder.Internal and Microsoft.AspNetCore.Http.Internal by making some types fully public and others fully internal.
Public:

• BindingAddress Move BindingAddress to public namespace #2979 - Used by Kestrel and HttpsRedirection
• BufferingHelper - Often used by customers.
• ApplicationBuilder - Used in many tests
• FormFile & FormFileCollection - Used in many tests, hard to replace.
• QueryCollection - Used by many tests

Internal:

• DefaultConnectionInfo/HttpRequest/HttpResponse/WebSocketManager/ItemsDictionary - Only used internally by DefaultHttpContext.
• RequestCookieCollection - Used by some tests but replaceable. (MVC, @pranavkm)
• ResponseCookies

[Tratcher]

Found a few more in in Http.Abstractions that all became internal:

• HeaderSegment
• HeaderSegmentCollection
• ParsingHelpers

[davidfowl]

When you write up the announcement for this make sure you mention some of the common alternatives to using these pubternal APIs

[Tratcher]

Can we do one announcement for all of #11312? Doing one for every feature area gets noisy.

[davidfowl]

Sure