Basic Layout Redesign

[lukasschor]

This ticket should aim to implement the basic layout redesign with the main changes being:

• Introduce sidebar
• Move main content elements

The goal should be to change as little as possible related to the logic of the main content elements (address book, tx list, safe apps, etc.) or the pop-up modals and adapt those elements to the new designs in a second step. Also, no need to add the red dot (signaling pending transactions) or make any changes to the Safe list sidebar.

So for example, there is no need to already move the Safe App list to the dropdown in the sidebar, we can just display the same content (combined app list and iframe) besides the sidebar.

Help Center

The help center sidebar item should lead here: help.gnosis-safe.io

[pablofullana]

relates to #910 ?

[lukasschor]

No. #910 is not needed, we don't need to make the web interface mobile responsive. See 5afe/safe-react-components#7