Remove stale usergroups

• Grazer BSD Stammtisch and Wiener BSD Stammtisch points to the same url
• The Swedish FreeBSD Community -> website down
• Ukrainian FreeBSD User Group (UAFUG) -> website down
• The Connecticut Free Unix Users Group (CFUG) -> Right now it's a personal blog
• Kansas Unix & Linux Users Association (KULUA) -> website down
• Phoenix BSD Users Group -> website down
• Greater Lansing Linux User Group -> website down
• Western Connecticut's Open Source User Group (WCOSUG) -> Commercial use
• The FreeBSD Mexican Community -> website down
• bug.dc.uba.ar -> website with another use
• The Daibou East *BSD Users Group (DEBUG) -> website down
• BSD Pakistan -> website down
• Mongolian Unix User Group (MUUG) -> website down
• Bangladeshi FreeBSD User Group -> website down

Approved by: bcr
Differential Revision: https://reviews.freebsd.org/D24533