maintain /fig - translate captions

[johnml1135]

From a user:

Copying the figures is more complicated with AI drafting than our old way. When we would copy figures to another project, we would have Paratext also copy the picture files to the project.
If we copy the picture files to a DZ, that does not get them to the main project where they will be needed and it does put them in the DZ project, where they are not needed and will just slow down the send/receive.
So we need another way to get the picture files to the main projects. One way is to copy them there on one of the computers (mine?) in an automatic, accurate, and reliable way so that all the projects have all the pictures they need. If we do that, we don’t have to copy the picture files to the DZ projects, just the \fig fields.

We should be able to maintain the fig links while translating the captions.