Add .editorconfig file (#6307)

.editorconfig

@@ -0,0 +1,15 @@
+root = true
+
+[*.{yaml,yml,yml.j2,yaml.j2}]
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true
+insert_final_newline = true
+charset = utf-8
+
+[{Dockerfile}]
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true
+insert_final_newline = true
+charset = utf-8