Enable FxCop code anayzers under project properties, and add an editor.config

**Is your feature request related to a problem? Please describe.**
Ensure that all contributors to the codebase adopt a common coding style so it is easy to pick up any code in the app and work with it if someone is familiar with the codebase.

**Describe the solution you'd like**
- Enable the built-in Microsoft Rosalyn Code Analyzers for FxCop under project properties dialog.
- Add or generate an editor.config for the solution.

**Describe alternatives you've considered**
Don't have an alternative, it would have to be a lot of effort in PR reviews!

**Additional context**
None.