Fuel plugin builder has no ability to define package dependencies

[Sergey Vasilenko]

Detailed bug description:
 Fuel plugin builder has no ability to define package dependencies for plugin in master node

Steps to reproduce:
  for example, my plugin requires 'patch' utility while install.
This utility was not installed while master node setup.
Pre-install script into RPM will be failed while plugin installed

Expected results:
  I need ability to define packages, that required for my plugin in format, like

    depends:
      - package: name1
        version: >=version1
      - package: name2

  into metadata.yaml

Actual result:
 I have no such ability.

Reproducibility:
 100%

Workaround:
 error-message while plugin install and fail installation.

Impact:
 fuel plugins