Revise entropy check to work without floating IP (#713)

* Revise entropy check to work without floating IP
* Bugfix: network must be passed to create_server
* Bugfix: set auto_ip=False
* Only consider image properties of public/community images. (#724)

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Signed-off-by: Matthias Büchse <[email protected]>
Signed-off-by: Kurt Garloff <[email protected]>
Co-authored-by: Martin Morgenstern <[email protected]>
Co-authored-by: Christian Berendt <[email protected]>
Co-authored-by: Kurt Garloff <[email protected]>