Update template_pi-hole_api.yaml

[Troug76]

Fixed template to access piHole API with {$HOST.IP}

[igorbach]

Hello!
If the custom ${HOST.IP} is required for template work - it should be defined on the template level
The same is for ${WEBPASSWORD} macro

Also, the syntax is confusing, better to use ${PIHOLE.HOST} and ${PIHOLE.TOKEN}