remove sourceforge projects

[mossmann]

Figure out what to do with the mailing list and then completely remove the project. https://sourceforge.net/p/forge/documentation/How%20to%20Remove%20a%20Project/

• [x] remove sourceforge and sf.net links from current repo
• [x] remove libbtbb from sourceforge
• [x] remove gr-bluetooth from sourceforge

[mossmann]

We were planning to remove the Ubertooth sourceforge project but decided to leave it for the purpose of hosting the mailing list archive.

[mossmann]

The mailing list has been closed, but the archive will remain.