RIO-41: eto os prepare (refat)

- google chrome workaround RIO-54
- access InstallCommand programmatically RIO-56
- eto os mirror RIO-57
- eto os mirror --stage3
- fixes packages perms
- os mirror RIO-41
- os mirror exclude fix
Merge pull request #7 from objectos/rio_41_eto_os

RIO-41: eto os prepare (refat)