[editorconfig] add rules for makefile, markdown, yaml, json and default

.editorconfig

@@ -0,0 +1,19 @@
+# https://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4
+
+[makefile]
+indent_style = tab
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.{json,yml,yaml}]
+indent_size = 2