Added standard .editorconfig file

.editorconfig

@@ -1,19 +1,17 @@
-# For more information about the properties used in
-# this file, please see the EditorConfig documentation:
-# http://editorconfig.org/
+# For more information about the properties used in this file,
+# please see the EditorConfig documentation:
+# http://editorconfig.org
 
-[*.php]
+[*]
 charset = utf-8
 end_of_line = lf
 indent_size = 4
-indent_style = tab
+indent_style = space
 insert_final_newline = true
 trim_trailing_whitespace = true
-max_line_length = 80
-
-[*.md]
-trim_trailing_whitespace = false
 
-[*.yml]
+[{*.yml,package.json}]
 indent_size = 2
-indent_style = space
+
+# The indent size used in the package.json file cannot be changed:
+# https://github.com/npm/npm/pull/3180#issuecomment-16336516