Adopt granary-model-dashboard

[James Santucci]

A while ago for fun times I made a dashboard for Granary models in Elm. Now it turns out we need one 😨 so we're going to assimilate it.

That involves several steps:

• the Granary README should include information for getting set up to do development of the dashboard (how to get the correct Elm extension for VSCode, how to get elm-format, first time app startup... basically all the tacit knowledge)
• the static assets for the dashboard should be served from the Granary server
• the dashboard should be built as part of the Granary CI process (probably this can just live in scripts/update or a more targeted script that can be called separately but is also card as part of scripts/update)
• the static assets for the dashboard should be bundled in the correct place into the published container
• the location of the Granary API should be parameterized like we do for Groundwork and different RF APIs not necessary, since we're serving from the same host 🎉

[Chris Brown]

Franklin has an example static service that serves files from the assets/ directory inside resources -- I think we can do something similar here