add dansguardian version 2.12.0.3

Comparison with the old dansguardian package from openwrt oldpackages:

1) Bumb Makefile from version 2.10.X to version 2.12.0.3.
2) New sourceforge location of the latest GPL software.
3) Applies the same configure patch that was needed for version 2.10 to make it work with openwrt.

Unchanged: DG needs more "power" than many embedded devices can provide (CPU / RAM / IO).