Support installing claw-playbook behind proxies

[Natkeeran]

When running claw-playbook behind proxies, it runs into two issue:

• apt_repository does not respect proxy settings. Thus, it fails in installing repos for php and imagemagick.
  We can manually install and continue:

sudo apt-get install software-properties-common 
sudo add-apt-repository ppa:ondrej/php 
Sudo add-apt-repository ppa:lyrasis/imagemagick-jp2
sudo apt-get update

• Second, it fails when adding Alpaca karaf repos

Need to manually install this to install all Alpaca repos:

/opt/karaf/bin$  ./client
karaf@root()> feature:repo-add reponame

It might be sufficient to add this to technical documentation, rather than work to address this issue depending on how many users may need to run/use Islandora 8 behind proxies.