linter: 💅 add .editorconfig

Author: maxbarsukov

.editorconfig

@@ -0,0 +1,21 @@
+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+indent_style = space
+indent_size = 2
+end_of_line = lf
+
+[*.{md,txt,markdown,eex}]
+trim_trailing_whitespace = false
+
+[{LICENSE,*.txt}]
+insert_final_newline = false
+
+[{Makefile,**.mk}]
+indent_style = tab