Add datasource `ovirt_vnic_profile`.

[jzandbergen]

Please describe the change you are making

Add the datasource ovirt_vnic_profile.

This because when using the resource ovirt_nic one needs to supply the vnic_profile_id attribute but it is nowhere exposed in the oVirt UI (4.5). This PR would make it easy to lookup this id by using a datasource.

Are you the owner of the code you are sending in, or do you have permission of the owner?

yes

The code will be published under the BSD 3 clause license. Have you read and understood this license?

yes

Notes

• I still need to handle a error in internal/ovirt/data_source_ovirt_vnic_profile_test.go:17 and would need some help with that.
• Could a PR like this be considered?

Thank you very much for your time.