Add hosts endpoint to get a host list

**Is your feature request related to a problem? Please describe.**
No. I can curl the endpoint, but this should be easier.

**Describe the solution you'd like**
Add a hosts mode and a list verb with available filters.

**Describe alternatives you've considered**
Curl works fine as shown in our docs: https://docs.datadoghq.com/api/latest/hosts/#get-all-hosts-for-your-organization
