Update Sourceforge to refer people to GitHub

[PaulWalkerUK]

The project needs to be left on Sourceforge for historical purposes (it might even be impossible to remove it anyway), but it needs updating so people know to come here for it now. It will also lend credibility to this being the new official home of the project if the old home refers to it.

[rlove]

sf.net Website and hosted documentation now have redirects to the current site.

http://utplsql.sourceforge.net/ -> https://utplsql.github.io/

utplsql.sourceforge.net/Doc/*.html -> https://utplsql.github.io/docs/index.html