Allow for locale copies in scripts

[andrewtavis]

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Issue

In discussing the project with @catreedle, we realized that it would be good to allow for some locales to be copies of others as the applications will sometimes not use one locale for a fallback - example of traditional vs. modern Indonesian as discussed in scribe-org/Scribe-Android#526. It would be great if the Python scripts would allow for copies of some locales to be made such that we can keep locales that are the same in sync.

[andrewtavis]

CC @catreedle, feel free to assign yourself this issue :)