Update/fix README links (Azure#4889)

* Fixing link to storage and event hubs.

* Fix broken links to Event Hubs. Convert tabs to spaces.

* Use relative links to source code. Remove en-us from docs.microsoft.com URLs.

* Remove en-us from identity/README.md

README.md

@@ -24,7 +24,7 @@ Each service might have a number of libraries available from each of the followi
 * [Management](#Management)
 
 ### Client: July 2019 Preview
-New wave of packages that we are currently releasing in **preview**. These libraries follow the [Azure SDK Design Guidelines for Java](https://azure.github.io/azure-sdk/java/guidelines/) and share a number of core features such as HTTP retries, logging, transport protocols, authentication protocols, etc., so that once you learn how to use these features in one client library, you will know how to use them in other client libraries. You can learn about these shared features [here](core). 
+New wave of packages that we are currently releasing in **preview**. These libraries follow the [Azure SDK Design Guidelines for Java](https://azuresdkspecs.z5.web.core.windows.net/JavaSpec.html) and share a number of core features such as HTTP retries, logging, transport protocols, authentication protocols, etc., so that once you learn how to use these features in one client library, you will know how to use them in other client libraries. You can learn about these shared features [here](core).
 
 These preview libraries can be easily identified by their folder, package, and namespaces names starting with `azure-`, e.g. `azure-keyvault`.