Adding designateext example networking

[beagles]

In real world use, designate's unbound, bind9s and/or mDNS pods all need to be accessible to "external" clients. designateext is used to simulate such a network. Note that even though it is is configured similar to the storage, internalapi, etc. networks, this is for testing and demonstration purposes only.

[openshift-ci]

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[openshift-ci]

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This pull-request has been approved by: beagles
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[beagles]

/test all