[web] Add community drawer to CommunityPicker

Summary:
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