[web] Add community drawer to CommunityPicker
linear issue: https://linear.app/comm/issue/ENG-2631/drawer-sidebar-inside-of-community-picker
The designs are not done yet, so styling will be updated later on.
Test Plan: Run the web app, checked that community drawer is present in CommunityPicker and behaves as expected.
Reviewers: ginsu, przemek, michal, tomek
Reviewed By: przemek, tomek
Subscribers: ashoat, tomek, atul
Differential Revision: https://phab.comm.dev/D6164