Added .editorconfig file (#3332) (#3313)

.editorconfig: specifying preferred indentation per file-type for the project.

Closes #3332, #3313

.editorconfig

@@ -0,0 +1,21 @@
+root = true
+
+[*]
+indent_size = 4
+indent_style = space
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[{Makefile,*.in}]
+indent_style = tab
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.{sh,ac}]
+indent_size = 2
+
+[Dockerfile]
+indent_size = 2