[tripleo-common] Select Networks Workflow

Implementation is very similar to https://blueprints.launchpad.net/tripleo/+spec/tripleo-common-select-roles-workflow

Provide a workflow which is takes a list of network names as input and populates network_data.yaml in container in Swift with respective networks from 'networks directory'

input: container, array of network names

1) validate that all networks specified as input exist in networks directory
2) for each network name from the input, check if it already exists in network_data.yaml, if yes, use that network definition (to avoid overwriting already specified configuration), if not, get the network definition from networks directory. Use the gathered networks definitions as input to updateNetworksWorkflow
3) run updateNetworksWorkflow with 'replace_all: true' which ensures that resulting network_data.yaml will contain only networks provided as input to this workflow

output: output of updateNetworksWorkflow (list of Networks from network_data.yaml)