Copy projects

[nbachiyski]

We need the ability to fork/branch/copy a project into a new project. The intended use case is for branching.

If we have wordpress/trunk at some point we need to create wordpress/2.8, which is a copy of trunk.

A copy means a copy of all original strings and a copy of all translations sets, connected with that project.

In the long term it makes sense to use copy-on-write. Most of the translations won't be changed after copying.

The feature can be a CLI script. It isn't necessary to be part of the web interface.

[pento]

This would be quite handy. Similar use, I've been creating a project for an app, then subprojects for each major version (strings only change between major versions).

So, my use case would be:
- Make a copy of a project.
- Upload a new set of originals, adding new strings, deleting strings that aren't in the new originals.