…okies as well...

…ng.. wierd one..

…uce warnings..

RequestContent: Don't use obsoleted property.
RestClientOptions*: use new RedirectOptions class instead for FollowRedirects.

…eQueryString

…erties.

… on rebasing...

…r newer VS versions.

…ragment tests.

Add secure test server untrusted certificate.
Out of paranoia, don't let SimpleServer use either the secure or insecure ports from TestServer.
Add tests both positive and negative for RedirectOptions.FollowRedirectsToInsecure

Remember to override options.RemoteCertificateValidationCallback if you get a certificate validation error in new tests.

Add changes to allow the AlterVerb... RedirectOptions to work properly.
RequestContent.cs: Add support for omitting the body (due to the HTTP Verb/Method changing under redirect processing)
TestServer.cs:
* Add certificate password for SSL test server.
* Add HTTP verb changing related routes
* Add dump-request route so that the method and hearders get dumped to response content to help enable authoring RedirectOption tests.
* Minor tweaks to silence nullability warnings.
RedirectTests.cs: Use new (Not)ContainCookieWithNameAndValue extension methods in tests, and use .And to cleanup the repetitive assertion code.
RedirectOptionsTest.cs:
* Add missing StatusCode assertions
* Use new (Not)ContainCookieWithNameAndValue extension methods in the tests and .And. to cleanup the assertions.
* For coverage reasons add initial request cookies to Can_RedirectForwardHeadersFalseWithCookie_DropHeaders.
* New tests:
Options.RedirectOptions.FollowRedirects = false
Options.FollowRedirects = False (back compat)
AllowForcedRedirectVerbChange = false with 302
AllowForcedRedirectVerbChange = false with 303
Change verb with defaults after 302
Change verb with defaults after 303
Don't chanve verb with defaults after 307
Options.CookieContainer contains expected results after a redirection.
Change verb with defaults after 303, but with ForceForwardBody so that the request body is forwarded on the new verb.

Additionally, due to having VS 17.9.3 updated xunit/ms test sdk nuget pkgs that makes some of the dependabot PRs obsolete.