Move trained data for scripts to new subdirectory

This fixes a name conflict for Lao.traineddata and lao.traineddata
which could not be distinguished on case insensitive filesystems
(for example macOS, Windows).

It makes it also easier for users to see which data is for scripts.
Choosing a script works now like this: tesseract -l script/Latin ...

Signed-off-by: Stefan Weil <[email protected]>

Author: stweil