Update Official HttpStatusCode

[caesar-chen]

We should update current HttpStatusCode to include more official status codes defined in recent RFCs.

Proposed API

    public enum HttpStatusCode
    {
        // Informational 1xx
        Continue = 100,
        SwitchingProtocols = 101,
+       Processing = 102,
+       EarlyHints = 103,

        // Successful 2xx
        OK = 200,
        Created = 201,
        Accepted = 202,
        NonAuthoritativeInformation = 203,
        NoContent = 204,
        ResetContent = 205,
        PartialContent = 206,
+       MultiStatus = 207,
+       AlreadyReported = 208,
        
+       IMUsed = 226,

        // Redirection 3xx
        MultipleChoices = 300,
        Ambiguous = 300,
        MovedPermanently = 301,
        Moved = 301,
        Found = 302,
        Redirect = 302,
        SeeOther = 303,
        RedirectMethod = 303,
        NotModified = 304,
        UseProxy = 305,
        Unused = 306,
        TemporaryRedirect = 307,
        RedirectKeepVerb = 307,
+       PermanentRedirect = 308,

        // Client Error 4xx
        BadRequest = 400,
        Unauthorized = 401,
        PaymentRequired = 402,
        Forbidden = 403,
        NotFound = 404,
        MethodNotAllowed = 405,
        NotAcceptable = 406,
        ProxyAuthenticationRequired = 407,
        RequestTimeout = 408,
        Conflict = 409,
        Gone = 410,
        LengthRequired = 411,
        PreconditionFailed = 412,
        RequestEntityTooLarge = 413,
        RequestUriTooLong = 414,
        UnsupportedMediaType = 415,
        RequestedRangeNotSatisfiable = 416,
        ExpectationFailed = 417,
+       ImATeapot = 418,

+       MisdirectedRequest = 421,
+       UnprocessableEntity = 422,
+       Locked = 423,
+       FailedDependency = 424,

        UpgradeRequired = 426,
        
+       PreconditionRequired = 428,
+       TooManyRequests = 429,
        
+       RequestHeaderFieldsTooLarge = 431,
        
+       UnavailableForLegalReasons = 451,

        // Server Error 5xx
        InternalServerError = 500,
        NotImplemented = 501,
        BadGateway = 502,
        ServiceUnavailable = 503,
        GatewayTimeout = 504,
        HttpVersionNotSupported = 505,
+       VariantAlsoNegotiates = 506,
+       InsufficientStorage = 507,
+       LoopDetected = 508,
        
+       NotExtended = 510,
+       NetworkAuthenticationRequired = 511,
    }

Details

Values added from WinRT: Windows.Web.Http.HttpStatusCode:

AlreadyReported
FailedDependency
IMUsed
InsufficientStorage
Locked
LoopDetected
MultiStatus
NetworkAuthenticationRequired
None (not sure what's this, not added)
NotExtended
PermanentRedirect
PreconditionRequired
Processing
RequestHeaderFieldsTooLarge
TooManyRequests
UnprocessableEntity
VariantAlsoNegotiates

RFC 2324:

ImATeapot

RFC 7450:

MisdirectedRequest

RFC 7725:

UnavailableForLegalReasons

RFC 8297:

EarlyHints

Related issue: #15650

/cc: @davidsh @karelz

[karelz]

The proposal is now moved back into #15650