vultr provider support

[luxiaba]

i want to add vultr provider and i found python-vultr, but seems that it hasn't been updated for a long time, and there are fatal bugs that can't be used normally, i write a new one pyvultr, can we use this to support vultr provider?

[laixintao]

Yes sure!

I think later we can move vendor's dependencies to optional, so users can install like this:

pip install lobbyboy[python-digitalocean]

[luxiaba]

Sounds great😋