Replace the convoluted useAccountSession composable with a pinia store
that in addition allows for the consolidation of all session related
functions to grouped into one module.
If a user logs out from a device the expectation should be that device
no longer having any association with the user's account. Any existing
push notifications should thefore be removed on server. For this reason
tie push notifications to a session, and remove them when the session is
deleted.
