Upgrade to Failure Discourse 2.8

[supermathie (Michael Brown)]

@Samir_Faci

cd /var/www/discourse/plugins && git clone https://github.com/pmusaraj/discourse-jitsi.git
fatal: destination path 'discourse-jitsi' already exists and is not an empty directory.
Cannot clone directory
cd /var/www/discourse/plugins && git clone https://github.com/paviliondev/discourse-question-answer.git
fatal: destination path 'discourse-question-answer' already exists and is not an empty directory.
Cannot clone directory

You’ve got these plugins (and more) listed somewhere twice.