Update install.md
Update install.md

remove integration server hosts as it's an internal process
change the repository address for front-demo project to the public one
open-orchestra/open-orchestra,open-orchestra/open-orchestra,alavieille/open-orchestra,alavieille/open-orchestra,open-orchestra/open-orchestra,alavieille/open-orchestra,open-orchestra/open-orchestra,alavieille/open-orchestra,alavieille/open-orchestra