Add .editorconfig

Introduce .editorconfig file into the repository.

Author: RauliL

.editorconfig

@@ -0,0 +1,16 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.{md,py}]
+indent_style = space
+indent_size = 4
+line_length = 79
+
+[*.yml]
+indent_style = space
+indent_size = 2