The lv_drivers provided monitor driver supports a `MONITOR_ZOOM`-factor
which scales the window by the set factor. This is 'useful when
simulating small screens'.
The zoom can be set as cmake configuration setting `-DMONITOR_ZOOM=1`.
Probably even more usefull for high-dpi screens where 240 pixels is
really tiny.
Implement the missing functions `xTimerGetExpiryTime()` and `xTimerIsActive()`
for the move of `TimerController` to use FreeRTOS timers.
In the process also fix a slight inaccuracy in the ms to ticks
conversion (no conversion was done as 1000 was close enough to 1024 for
a first working implementation).
Fixes: https://github.com/InfiniTimeOrg/InfiniSim/issues/17
