CLI command to export locations configuration

[adidanes]

Is your feature request related to a problem? Please describe.
It can be usefull to export locations definitions to a file, then possibly modify it and apply it to make configuration changes.

Describe the solution you'd like
A cli locations sub-command allowing to export locations details to a yaml or json file,

Something like:
yorc locations export

Flags:

--output or -o: Output format, yaml or json (default yaml)
--file or -f: Path to a file where to store the output (default standard output)