Add the DCD module donated by Atruvia AG

[lgetwan]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

There was no DCD module

What is the new behavior?

• There is a DCD module

Other information

There is no PUT endpoint in the REST API for the DCD, so it's not possible to update existing DCD connectors.

[lgetwan]

Next week, we'll get the integration tests running, as well. ;-)

[robin-checkmk]

The documentation does not state, that this option is required, but the module fails without it.
I am torn between seeing this as an error, as it is technically a valid use case to not restrict source hosts, but the collection being stricter here, might help users avoid errors.

[lgetwan]

I left it "optional", but have set the default to an empty list, now.

[github-actions]

This pull request has been stale for 60 days. It will close in 7 days.

[lgetwan]

We should trigger the integration tests...

[lgetwan]

@robin-checkmk
I cleaned up a lot.
Open topic is still the usage of "DCD" vs. "Dynamic Host Management"

[lgetwan]

I added the parameter "matching_hosts", that I somehow forgot to implement before. :-p

The module looks complete from my point of view, now.