Add table for `datadog_host`

[marcus-crane]

Tables added

+------------------------------------+-------------------------------------------------------------------------------------------------------------------------+
| table                              | description                                                                                                             |
+------------------------------------+-------------------------------------------------------------------------------------------------------------------------+
| datadog_host                       | A host is any piece of infrastructure that runs an instance of the Datadog Agent such as a bare metal instance or a VM. |
+------------------------------------+-------------------------------------------------------------------------------------------------------------------------+

Closes: #19

This is my first steampipe contribution so I expect I might have overlooked some things but I've tried to adhere to the style of the existing tables where possible.

There are a few things worth pointing out:

• While I've tried to wire up pagination properly, my workplace doesn't actually have enough hosts to properly test that it actually works (the page limit is 1000+)
• I don't really understand the specifics of hydration when it comes to the absence of something. The Datadog hosts API will apparently serve results for any host that is live within the last 3 hours by default. Presumably if you were to open Steampipe, close it then open it again in a week, Steampipe would still retain older hosts rather than magically setting up to false. If Steampipe removes an entry from the table upon trying to rehydrate it and getting a 404, then this isn't such a big deal but either way, it kind of makes the up field redundant if it is always set to true
• While I tried to craft some more "Advanced" queries, I'm not that great with SQL so some queries can probably be rewritten to be less complex
• I haven't mapped host_name, which is available in the hosts API, as it appears to contain the exact same data as name based on the description.

Anyway, I didn't worry too much about the edge cases since they can be ironed out over time I'm sure.

You can do quite a lot of fun queries by making use of jsonb which I've heard about for a few years now but I've never actually seen it in action before now.

[marcus-crane]

@LalitTurbot Heya, just wanted to bump this PR since it's been ready for review for some time 😅

[cbruno10]

Hey @marcus-crane , sorry for the very long delay on reviewing, we missed a few open PRs recently, but are circling back on them. We'll have a few done in the next few days.

Thanks again for opening this PR!

[github-actions[bot]]

'This PR is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 30 days.'

[marcus-crane]

Ah, hey! Sorry, I hadn't gotten back to addressing your feedback but I hadn't forgotten 😅 It's been a while so I've forgotten some details but I'm happy to open another PR with improvements down the line 😀