Fix failing URL status checking integration tests

Implement following redirects over `fetch` supporting cookies.
`node-fetch` does not support sending cookies during redirect. However,
this is needed to not end-up in a redirect loop for a sign-in callback.

Fix integration tests failing due to redirects and 403 errors:
  - Many redirects from `answers.microsoft.com` was throwing: throwing
    `FetchError: maximum redirect reached` error. It was caused by not
    having cookies when following redirects therefore having an infinite
    sign-in callback for the webpage.
  - Fixes integration tests failing due to additional referer header being
    sent by the application. It adds support for making exceptions to
    additional header sending through a list of regexes.

Add in-depth documentation for URL status checking.

tests/integration/application/collections/StatusChecker/ExponentialBackOffRetryHandler.ts

@@ -25,8 +25,8 @@ function shouldRetry(status: IUrlStatus) {
     if (status.error) {
         return true;
     }
-    return isTransientError(status.statusCode)
-        || status.statusCode === 429; // Too Many Requests
+    return isTransientError(status.code)
+        || status.code === 429; // Too Many Requests
 }
 
 function isTransientError(statusCode: number) {