New handling of /user files (-> *.dist files for easier updates)

I provided two separate archives until now: One for installation,
one for update. The only difference between them was that the update
archive did not contain the /user sub-directory to keep use-defined
changes.

However, this was too complicated for many users as only my templates
were delivered with as two separate archives. So I changed my mind
and use /user/*.dist files to provide examples and templates. These
files are dummies and may be overwritten. However, the user can take
and just remove the ".dist" extension to use them as starting point
for own modifications.