Add EditorConfig [ci skip]

Ref:
  - http://editorconfig.org/

Author: PeterDaveHello

.editorconfig

@@ -0,0 +1,8 @@
+root = true
+
+[{*sh,*.md,*.yml}]
+indent_size = 2
+charset = utf-8
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true