[TASK] Add an .editorconfig file

This configuration has been copied from the TYPO3 coding standards
package.

This allows IDE to use the correct indentation style when editing
files.

Author: oliverklee

.editorconfig

@@ -0,0 +1,13 @@
+# EditorConfig is awesome: http://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+indent_size = 4
+insert_final_newline = true
+trim_trailing_whitespace = true