[web] Introduce navigation arrows

Summary:
Add arrows that allow users to navigate forward and backward in history.
https://www.figma.com/file/a1nkbWgbgjRlrOY9LVurTz/Comm-%2F-Desktop-app?node-id=1272%3A88750

Test Plan:
Open the app and check if arrows are displayed correctly.
Click right arrow - nothing should change.
Do a couple of tests by clicking left and right arrows, both in app and in the browser and by clicking some links. Everything should work.

Reviewers: def-au1t, atul, benschac

Reviewed By: atul

Subscribers: ashoat, Adrian, yayabosh

Differential Revision: https://phabricator.ashoat.com/D4138