More glanceable breakdown of pros and cons of self-hosting

> It would be great to include this disclaimer on all the set-up pages (I am thinking the DigitalOcean installation page for example). For older users like myself, who installed ODK before ODK Cloud was an option, it would be great to have that disclaimer front and center, so we can make informed decisions about web-hosting in the future.
-- User feedback.

Not sure if this should live in the docs or on the website, but something like https://docs.getodk.org/security/#hosting-considerations or https://ghost.org/docs/hosting/#ghostpro-vs-self-hosting would be great to have up-front.

Start with the existing hosting considerations section at docs.getodk.org/security/#hosting-considerations and the DigitalOcean installation page mentioned in the issue. Determine whether the proposed comparison belongs in the documentation or website, then identify the relevant setup pages and define completion as a clear, upfront breakdown of self-hosting pros and cons across them.

Written by the indexing model from the issue text.