When updating, project and file indexes must be rebuilt or backed up #620
Description
When installing the package, edoc/index will be overwritten, hence both index files will be empty. This means that though all projects and files are still in the DB, wdb+ won’t find them.
Either, we need a pre-install to back these two files up and put them back in post-install (preferred), or run index-projects.xq in post-install (shouldn’t take too long as it just goes through the wdbmeta files, but still)