Sync between devices

**Purpose**
When a user clocks out on a different device than the one they used to clock in, we should sync the clock out with the device that was used to clock in.

** Description **
Right now, when the user clocks out on a different device, the device used to clock in will keep showing the user as clocked in and the clock will still be counting, until the user reloads the page.
Ideally we want to notify the first device so that it shows the user as clocked out.

**Acceptance Criteria**
- When the user clocks out on one device, the clock will stop and the user will be shown as clocked out on all devices on which they are logged in.

**Scope**
Common use case: I use my phone for clocking out, because I forgot to do it while my computer was still turned on.