Add .editorconfig for ensuring some consistency

.editorconfig

@@ -0,0 +1,23 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+charset = utf-8
+
+[*.nix]
+indent_size = 2
+trim_trailing_whitespace = true
+
+[*.md]
+indent_size = 2
+trim_trailing_whitespace = false
+
+[*.json]
+indent_size = 2
+trim_trailing_whitespace = true
+
+[*.yaml]
+indent_size = 2
+trim_trailing_whitespace = true