Tools/scripts: update port_conflicts_check.lua

This update provides the following enhancements:

• The list of all files of all packages in the official repository is directly parsed from a dump of the provides.db database, instead of parsing the output of "pkg provides".

• If a package uses a version specific sub-directory as is the case for e.g. most perl or python modules, a pattern that is generated that matches only other modules built for the same interpreter version.