📄 Provide guidance on performance tradeoffs with comparable platform choices (pure native, web view, etc.)

[chrisglein]

We regularly have app authors asking for guidance on which is the best option for them for how to architect their app. Example options:

• Pure native (UWP/XAML)
• React Native for Windows
• A web view in a container Win32 app (e.g. Electron)
• Hybrid (e.g. UWP app that has WebView for a large section of its app)

All of these have valid uses. And all of them have tradeoffs. We should write down some guidance on when apps may or may not want to prefer React Native for Windows.

To support this we should provide data where we can. Some of that can be gathered with sample/reference apps that are as close to apples to apples comparisons as we can. Some would depend on data from real apps in market, which we may not have or may not be able to share. But let's provide what we can here for the general audience.

[jonthysell]

Working on this, but not for 0.66.