(improvements) Navigation menu

[alexstotsky]

Task: https://app.asana.com/0/1163495710802945/1206521519232850/f

Description:

• Enhances Reports navigation menu representation according to the following improvement proposals

We want to tighten up the navigation bar:
- The items that are not active should be grey instead of white
- Parents and sub-items both
- The sub-items should have a reduced line height so that more items will fit
- The sub-item that's active should have a background covering the entire width
- The sub-item should be properly aligned with the parent 

Before:

nav-menu-before.mov

After:

nav-menu-after.mov

[ezewer]

lgtm!