Add editor config settings for IDE's that support it

see https://editorconfig.org/

Author: Paweł Niedzielski

Diff for: .editorconfig

@@ -0,0 +1,23 @@
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+trim_trailing_whitespace = true
+
+[*.js]
+indent_style = space
+indent_size = 2
+
+[*.php]
+indent_style = space
+indent_size = 4
+
+[{package.json, *.yml}]
+indent_style = space
+indent_size = 2
+
+[*.md]
+trim_trailing_whitespace = false