Remove capistrano, can still be used at mconf/mconf-web-caphub

Deploy with capistrano is now made using caphub, see
https://github.com/mconf/mconf-web-caphub
Remove old installation scripts, refs #638

They are not used anymore, installation now only via wiki or capistrano, see
https://github.com/mconf/mconf-web/wiki/Mconf-Web-Deployment