Implemented differents methods for creating and caching HttpMessageHandler

[dimysa]

Description

Now, if we go in to get a new HttpMessageHandler for another HttpClient, we get the same HttpMessageHandler. And if HttpClient is disposed, then HttpMessageHandler will also be disposed, which will make other HttpClients not work

API Changes

Added:

• bool HttpMessageHandlerProvider.CreateOrGetCachedDefaultHandler()

Changed:

• bool HttpMessageHandlerProvider.CreateDefaultHandler()

Platforms Affected

• Core (all platforms)

Behavioral/Visual Changes

None

Before/After Screenshots

Not applicable

PR Checklist

• [x] I have read the CONTRIBUTING document
• [x] My code follows the code styles
• [x] Targets the correct branch
• [x] Tests are passing (or failures are unrelated)