Move terminal CSS into LESS file

IPython/html/static/notebook/less/terminal.less

@@ -11,3 +11,7 b''
   color: black;
   background: white;
 }
+
+#terminado-container {
+    margin: 8px;
+}

IPython/html/static/style/style.min.css

@@ -10495,4 +10495,7 b' span#autosave_status {'
   color: black;
   background: white;
 }
+#terminado-container {
+  margin: 8px;
+}
 /*# sourceMappingURL=../style/style.min.css.map */

  No newline at end of file