add .editorconfig [skip ci]

Signed-off-by: Julien Veyssier <eneiluj@posteo.net>

.editorconfig

@@ -0,0 +1,25 @@
+# https://editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = tab
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.feature]
+indent_size = 2
+indent_style = space
+
+[*.yml]
+indent_size = 2
+indent_style = space
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.svg]
+insert_final_newline = false