Add `deploy_node` for DigitalOcean

## Feature Request

Currently DigitalOcean driver has no `deploy_node` method (only `create_node`).
I couldn't find a way to use MultiStep deployment options with `create_node` (install a `salt-minion` right after installation)
From what I could see so far, the only way to use DigitalOcean driver is using `create_node` directly (which works perfectly).

Start with the DigitalOcean driver's existing create_node entry point and trace how deployment options are handled elsewhere in the project. Define what deploy_node must do to support MultiStep deployment, including installing a salt-minion immediately after node creation, and verify that the resulting workflow works without breaking the existing create_node behavior.

Written by the indexing model from the issue text.