Add .editorconfig for consistent C# code style

Author: rustampulatov8

.editorconfig

@@ -0,0 +1,27 @@
+# EditorConfig helps maintain consistent coding style across editors
+root = true
+
+[*.cs]
+indent_style = space
+indent_size = 4
+insert_final_newline = true
+charset = utf-8
+trim_trailing_whitespace = true
+
+# C# code style rules
+dotnet_sort_system_directives_first = true
+dotnet_separate_import_directive_groups = true
+dotnet_style_qualification_for_field = false
+dotnet_style_qualification_for_property = false
+dotnet_style_qualification_for_method = false
+dotnet_style_predefined_type_for_locals_parameters_members = true
+dotnet_style_predefined_type_for_member_access = true
+csharp_new_line_before_open_brace = all
+csharp_indent_case_contents = true
+csharp_indent_switch_labels = true
+csharp_space_after_cast = false
+csharp_space_after_keywords_in_control_flow_statements = true
+csharp_space_before_open_square_brackets = false
+csharp_space_around_binary_operators = before_and_after
+csharp_preserve_single_line_statements = false
+csharp_preserve_single_line_blocks = false