Werk #11117: Drop support for creation of HostLabels via discovery function

Component	Checks & Agents
Title	Drop support for creation of HostLabels via discovery function
Date	Oct 11, 2020
Checkmk Editon	Checkmk Raw (CRE)
Checkmk Version	2.0.0i1
Level	Trivial Change
Class	New Feature
Compatibility	Incompatible - Manual interaction might be required

This werk only affect users who implemented their own plugins *and* where creating HostLabels using the discovery function.

Plugins trying to create HostLabel instances will fail with a NameError.

The afore mentioned feature is no longer supported. Creation of host labels can now only be implemented using the new check API. It is done by passing a `host_label_function` to the `register.agent_section` function. For details please refer to the dokumentation.

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