support proxy in repo file settings

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
add proxy kw into yum repo templates

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
disable proxies for apt when needed

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
Merge pull request #188 from alfredodeza/8131

ensure no proxies are set for calamari