electron-kiosk

Add timer to check for AXiS->Hx downtime mode.

- Adds timer to check for HealthTrax downtime by calling AXiS /downtime
  url. This includes settings downtimeUrl, which states downtime will be
  active soon or not.
- downtimeActiveTimeout means to refresh the page quicker until the downtime
  page shows
- downtimeInactiveTimeout is for checking the AXiS /downtime api to see
  if ekiosk should start refreshing soon.

for HEAL-2129