Add option to only store ID if speaker is sourced from PopIt?

[jpmckinney]

https://github.com/openpolis/poplus-pci takes a "no-database" approach for composing different components. SayIt takes a "master-slave" approach: it treats a PopIt instance as the master, and doesn't push any edits to speakers to PopIt. Should there be an option to have SayIt operate using a "no-database" approach for speakers, i.e. SayIt only stores the PopIt identifier for a speaker, and when speaker data is needed, it queries the PopIt instance, like poplus-pci?

/cc @guglielmo