Change Domain to IP in API_URL

[darkexplosiveqwx]

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What does this PR aim to accomplish?:

Fixes #448

How does this PR accomplish the above?:

This changes API_URL to be https://192.160.0.1:443/api/ instead of https://pi.hole:443/api/ by taking the server specified with --server.
This fixes the client not using the pihole its PADDing to a DNS since webserver.domain doesnt need to be resolved anymore.
Additionally this will lower the outgoing DNS requests for webserver.domain, why would we need to resolve that if we already know the ip of the server.
When specifying a hostname with --server, it was already checked in the beginning that the hostname is avalible via the systems DNS. (with cmdResult="$(dig +short chaos txt domain.api.ftl @"${SERVER}" 2>&1; echo $?)")

Link documentation PRs if any are needed to support this PR:

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