Verify configmap properties

[LionelJouin]

The NSP is for now only verifying the validity of the resources in the configmap. For example a Flow referring to a non existing stream will be drop and be considered as invalid until the stream is created. The dropped resources will not be send when other components (LB, proxy...) will watch the resources.

https://github.com/Nordix/Meridio/blob/master/pkg/configuration/reader/model.go

• [ ] validation of: IP, Prefix, Port, port-range, protocol...., drop the resources with invalid attributes
• [ ] Handle duplicates. e.g. If 2 VIPs have the same address, what would happen if the 2 VIPs are added on the interface by the ambassador and if one of the 2 VIP is removed.

This can be done here: https://github.com/Nordix/Meridio/blob/master/pkg/configuration/reader/converter.go And common pkgs (to re-use on the operator) could be created on this Meridio repo.