threadloop: fix deadlock issue

start() can deadlock into join if a previous stop has been called and
the thread hasn't seen it before started again.

This patch solves that by using a transactional stop (using FSM).
This also adds MoveConstructible and MoveAssignement behaviour.

Issue: #80556
Change-Id: Ie04e3a20007e69b4d372b9619d67710f4e2af1b7