Summary:
This commit adds a new action, `moveThreadsToPerspective` to be proxied and
measured through the ThreadListActionsStore. This action is called when
a thread or group of threads is dragged and dropped into an item in the
sidebar.
For now, we are only interested in timing actions that remove threads
from the inbox
Depends on D3984
Test Plan: manual
Reviewers: halla, evan, spang
Reviewed By: evan, spang
Differential Revision: https://phab.nylas.com/D3985