Fix stale 'Host class' reference in getting-started.md

[jtdub]

Description

In docs/getting-started.md:15, there is a stale reference from a previous version:

With the Host class imported, it can be utilized to create host objects.

The Host class was removed in v3. This sentence follows the import of WorkflowRemediation, get_hconfig, and Platform — none of which is a "Host class."

Fix

Remove or replace the sentence. Suggested replacement:

With these imports, you can create configuration objects and compare them.