Implement the new top bar and remove the sidebar

[slaweet]

Subtask of #1645
The goal is to implement this top bar:

https://netguru.invisionapp.com/share/X9PMLKSUNYE#/screens/339319711

Specification

• Menu items should go to pages as they do in sidebar
• "Delegates" menu item should be displayed only if enabled in settings
• "Sidechains" page should be removed from the menu and from the code
• Account address should have the copy icon next to it and work as before
• The avatar should on click show dropdown menu implemented in Implement the new menu avatar dropdown #1647
• The search bar should work with suggestions as before (maybe look of it can be slightly adjusted to the new colors in no more than 30mins)

[osvaldovega]

issue fixed in PR #1674