Add the template files as links to the ATxService project, pointing to
the central "Solution Items" files and mark them for copying to the
build output location. Update the Make-Package script accordingly.

Refers to #28

Refers to #13

Refers to #2

Refers to #3

Plus also check if the repository's commit state is dirty and report
accordingly.

This is done using a git-hook script generating a text file which is
used as a resource by VS. The pre-build script in VS makes sure the file
is actually existing (using a default string) since otherwise the build
would fail.

The previously used "Resources" folder is not a good location for them
as they are not really part of the application itself.