No override option in TV Mode/Full Screen on Dashboard

## Expected Behavior

When changing to Full Screen mode on Dashboard all Widgets will render with each time range, but if I want to override all widgets time range i.e. to last hour and change to Full Screen/TV Mode this option is not enforced.

## Current Behavior

All widgets is setted to "No override" option and will render with each time range

## Possible Solution

On "Configuring Full Screen" I have 3 options: Refresh Interval, Tabs and Tab cycle interval. How about make another option "Override" or "Time Range".

## Steps to Reproduce (for bugs)

1. Override all time range of widgets
2. Change to Full Screen/TV Mode

## Context

## Your Environment

* Graylog Version: 3.2.4
* Elasticsearch Version: 6.5.4
* MongoDB Version: 3.6
* Operating System: FreeBSD 11.3 STABLE