Add SocketRocket Security Policy Provider

[djorkaeffalexandre]

Summary:

When you have a server that is under a Client Certificate logic, and has some connection to it using websockets, you can't provide the security policy to the instance created for the socket on RCTWebSocketModule.

Following what we have for RCTNetworking where you can inject a custom configuration for the URLSession created, these changes aim to implement a similar way to provide a custom handler for creating a Socket Rocket SecurityPolicy based on the request that will be sent through the socket.

SRSecurityPolicyProvider providerBlock = ^SRSecurityPolicy *(NSURLRequest *request) {
  if (request.URL == @"myclientcertificate.domain.com") {
    return ...;
  };
  return NULL;
}
  
RCTSetSRSecurityPolicyProvider(providerBlock);

Changelog:

[IOS] [CHANGED] - Add SocketRocket Security Policy Provider

Test Plan:

I can't provide my own server with the client certificate here, but the important piece of code is above, this is a customization that is important to react-native developers, for Android we already have a way to customize the OkHttp instance being used by the socket, that I proposed some time ago, so this new api will make it easier for developers to inject custom websocket security policies for iOS too, since they will not need to do any method swizzling or fork of react-native.