Replace the digital_ocean modules with digital_ocean_droplet and digital_ocean_sshkey

[daraul]

The digital_ocean module was removed in ansible v2.12. They recommend using the digital_ocean_droplet module instead.

https://docs.ansible.com/ansible/latest/modules/digital_ocean_module.html#id1

[juanluisbaptiste]

@daraul or whomever needs this role, I have updated the do modules plus other fixes on my fork. If @jasonheecs is interested I can create a PR to merge my changes here.

[jasonheecs]

Hi @juanluisbaptiste, I would definitely welcome a PR :)