Get modulename via function; set kwrepo attribs via direct reference

Move all that can be done only once per repo into reposetup Actually kwrepo is not set up if there aren't any files configured for keyword substitution. Stuff that now is done at reposetup and not at every filelog init or hook: 1) filename matching function 2) compilation of keyword regex 3) templates and changeset templater kwtemplater as an appended class should prevent namespace conflicts.

Extend templater.common_filters in kwtemplater