clean up jekyll-theme-console copy, add license notice

.gitmodules

@@ -1,3 +0,0 @@
-[submodule "_vendor/jekyll-theme-console"]
-	path = _vendor/jekyll-theme-console
-	url = https://github.com/b2a3e8/jekyll-theme-console

_sass/base.scss

@@ -1,7 +1,10 @@
 @charset "utf-8";
-// @import url('https://fonts.googleapis.com/css?family=Rubik:400,700');
-// @import url('Rubik-VariableFont_wght.ttf');
 
+// License notice: derived from
+// https://github.com/b2a3e8/jekyll-theme-console
+// MIT License, Copyright (c) 2018 b2a3e8
+
+// local distribution instead of Google CDN usage
 @font-face {
    font-family: 'Rubik';
    src: url('fonts/Rubik-VariableFont_wght.ttf') format('truetype');

_vendor/jekyll-theme-console

@@ -1 +0,0 @@
-Subproject commit 76983908faa6f06ffd87b70165f2632790d36687