* Fix all stylelint errors
For any errors that fixing would require changing the output of the css disable stylelint for that line instead of modifying.
* Update quality.py
Make stylelint quality check pass when there are no errors
* Delete empty selectors
LEARNER-1785
This story was to update the existing custom themes to work with the flexible bootstrap design. It also updates the red theme to more closely resemble the real implementation on openedx.