Allow Ping to support multiple IP address per device

Continuing the discussion from 0.115: B-Day release! Media browser, tags, automations & WTH:

from Apple iOS 14.x, devices can get a network dependent Mac-address. This complicates the Ping device_trackers and sensors in HA, which are setup using a fixed (reserved) ip-address on the router.

A single mobile device receives multiple Mac-addresses, and because of that multiple ip-addresses.
One could of course create ping sensors for all of these ip-addresses, but considering each household is likely to have multiple devices, this could soon become a large setup.

Please consider adding multiple ip-address support for the Ping integrations in HA

 - platform: ping
    interval_seconds: 60
    consider_home: 180
    hosts:
      ping_iphone_multiple_addresses: 192.168.1.56,192.168.1.57,192.168.1.58,192.168.1.59