feat: add kemp cluster support

[7meis]

General information

Kemp Loadmasters can be set up in HA mode, which means there are two Kemp Loadmasters running in active-passive mode. This configuration ensures that the virtual services running on one of the two nodes at this point in time can be mapped.

Proposed changes

• What is the expected behavior? -> Clustered Kemp Virtual Services are possible
• Consider writing a unit test that would have failed without your fix. -> I have unit tests, but I don't currently know where best to integrate them. Since I've never done this before, with a little help, I can do it. See: http://github.com/WagnerAG/checkmk_kemp_loadmaster/tree/main/tests/unit/cmk/plugins/collection/agent_based

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[7meis]

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