added editor config

Author: Marvin Kuhn

.editorconfig

@@ -0,0 +1,21 @@
+; This file is for unifying the coding style for different editors and IDEs.
+; More information at http://editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+indent_size = 4
+indent_style = space
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[.html,.yml,.yaml]
+indent_size = 2
+
+[*.xlf]
+insert_final_newline = false
+
+[*.md]
+trim_trailing_whitespace = false