Update sub navigation styles for desktop and mobile

In an effort to have better styling consistency between the various RH properties and reduce some confusion with our usage of arrows, we need to update our sub navigation styles.

Normal state
1) Remove ALL arrows
2) Remove uppercase
3) Make base color text #656565
4) Text Flush left
5) Add a bottom rule for visual separator: 1px solid #BDBDBD;

Active State:
1) Text color: black
2) Add a bottom rule for visual separator: 2px solid #CC0000;

For mobile:

1) Do all of the changes for the desktop
2) hanging the menu button color to background color to #424242

@media only screen and (max-width: 768px)
.side-nav li.side-nav-toggle {
background: #424242;

tnolan@redhat.com - For tracking.

Definition of Done

1. Requester has approved implementation.