Enable download of project with a filter to include/exclude certain files or filetype

[raherin]

In many cases we need to download a previous version of a project but only need the project files. In these cases, it would be useful to be able to add a filter to the project download, for example to exclude all media files, so we aren't downloading several GBs of data when we only need the project and config files.

[dracic]

And also this would be useful in db-sync. No need to download all images to sync gpgk to PostgreSQL.