Document how to connect from a mobile app to local web app in the same solution

Moved from #3746
@danroth27 wrote:

We should update this article with more detailed steps on how to connect from the mobile app emulator to the web api when both are in the same solution. Ex. with the Android emulator you use IP address 10.0.2.2 and you need to update your IIS Express site bindings to allow the request through. We should also figure out what the steps are for iOS or UWP.

Nov 2019 6K PV


---
#### Document Details

⚠ *Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.*

* ID: bdbdf1ed-c52a-3be8-1f41-aecbdab0883b
* Version Independent ID: d06996cc-14aa-96e2-fd62-9d5bbc059107
* Content: [Create backend services for native mobile apps with ASP.NET Core](https://docs.microsoft.com/en-us/aspnet/core/mobile/native-mobile-backend?view=aspnetcore-2.2)
* Content Source: [aspnetcore/mobile/native-mobile-backend.md](https://github.com/aspnet/Docs/blob/master/aspnetcore/mobile/native-mobile-backend.md)
* Product: **aspnet-core**
* GitHub Login: @ardalis
* Microsoft Alias: **riande**