feat: http_proxy support added

• vagrant propagation from host to guests:

  • requires vagrant-proxyconf plugin (https://tmatilai.github.io/vagrant-proxyconf/)

• http_proxy configuration for docker service.

• Following tests passed:

  • no proxy configuration without plugin.
  • no proxy configuration with plugin.
  • proxy configuration with plugin.

• Proxy configuration not supported on the CI/CD.