Add .editorconfig

.editorconfig

@@ -0,0 +1,34 @@
+# Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 4
+trim_trailing_whitespace = true
+
+[*.{cs,vb}]
+dotnet_sort_system_directives_first = true
+
+[*.cs]
+csharp_indent_case_contents = true : error
+csharp_indent_switch_labels = true : error
+csharp_new_line_before_open_brace = all
+csharp_prefer_braces = true : error
+csharp_style_expression_bodied_methods = when_on_single_line : suggestion
+csharp_style_expression_bodied_constructors = when_on_single_line : suggestion
+csharp_style_expression_bodied_operators = when_on_single_line : suggestion
+csharp_style_expression_bodied_properties = when_on_single_line : suggestion
+csharp_style_expression_bodied_indexers = when_on_single_line : suggestion
+csharp_style_expression_bodied_accessors = when_on_single_line : suggestion
+csharp_style_var_elsewhere = true : suggestion
+csharp_style_var_for_built_in_types = true : suggestion
+csharp_style_var_when_type_is_apparent = true : suggestion
+dotnet_style_qualification_for_event = true : error
+dotnet_style_qualification_for_field = true : error
+dotnet_style_qualification_for_method = true : error
+dotnet_style_qualification_for_property = true : error
+
+[*.targets]
+indent_size = 2