Initial commit of cms and lms python, html, css and js changes

@jrbl & @stvstnfrd - making it possible to add arbitrary HTMl to course_about sidebar
We should be constructing this string with `format`ting, not
concatentation.

```python
anchor = '<a class="link-courseURL" rel="external" href="{href_url}">{href_text}</a>'
anchor = anchor.format(
    href_url=lms_link_for_about_page,
    href_text=_("your course summary page"),
)
```

This is easier to mentally parse.