NetworkConfigSection type only supports single NetworkConfig

[tlawrence]

In order to add multiple networks to a vApp in a single call, NetworkConfigSection should support an array of "NetworkConfig" type. currently only a single is defined.

Not sure how best to implement this. Really the current implementation should be changed but I guess there is a lot of stuff downstream which may depend on th ecurent implementaition.
I guess you could add a "NetworkConfigs" type and make that optional on NetworkConfigSetion..

https://github.com/vmware/govcloudair/blob/f951754902a8f8ebcbd51812ac79b1ec61a7ce09/types/v56/types.go