Update to project templates to use .Targets files instead of individual references

While creating New samples and the NuGet installer thee was an increasing need to simplify how to reference MonoGame libs and dependant references.

SO I've crafted .Targets files for each supported platform. updated the project templates to use them and the build installer to copy the .targets files

Updated:
* All project templates except iOS / MacOS
* Build installer to copy new .target files
Added:
* .Target files to Project templates folder