Add quick .editorconfig

Should limit obvious formatting woes until we get our .clang-format game 
together

.editorconfig

@@ -0,0 +1,17 @@
+# https://EditorConfig.org
+
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+indent_size = 3
+
+[{Makefile,*/Makefile,*.mk,*_rules}]
+indent_style = tab
+indent_size = 4
+
+[*.yml]
+indent_style = space
+indent_size = 2