Document Host Managed Deployments

[mattmathis]

Remove all documentation on obsolete deployment models

First draft of the new Host Managed Deployments

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This change is 

[newcombms]

_pages/09-contribute.md line 40 at r1 (raw file):

It is now easier than ever to contribute to the Measurement Lab platform.  The process is almost entirely automated and any reasonably modern, high performance and well connected physical or virtual server can be added to M-Lab's fleet.

Review M-Lab's [Acceptable Use Policy](https://www.measurementlab.net/aup/), [Privacy Policy](https://www.measurementlab.net/privacy/), and the technical and operational requirements at the top of [Setting up a host-managed server](https://github.com/m-lab/autonode/wiki/Host%E2%80%90managed-Deployments).

Flagging that we still need to finalize the AUP and remove the old MOU template across the website