Add hover descriptions for icons when hovering over them.

I had a few colleagues highlight that with many icons, it is impossible to know what they are until they are actually clicked. Often, on other platforms, if you hover over an icon a short description pops up, which can be very helpful, especially when learning how to use the software. I've attached an example of this on Facebook and a screen shot of the CRM with red arrows highlighting the examples of icons where pop up description could be helpful.