Improve setup provisioning task

Update yum call to not ask for confirmation, update required packages
and silent some commands outputs. Also drop call to network start in
favor of later restart.
Merge pull request #73 from elyezer/improve-setup-provisioning

Improve setup provisioning task
Update docs to document product_install usage

Product install task is now a single task which is able to install
product for all distributions: cdn, downstream, iso and upstream.

Closes #67.