Restore demos, document their config API and how to set up static-hosted and docker installations about schemarama HOT 2 OPEN

Started a rough script that copies things into the right place in an ephemeral "_serving" folder.

• it takes everything from demo/static/
• bit of care about symlinks between the js/ directories and core/dist/ originals
• it deals with the 6 "Config API" URL paths, either copying original files or for the JSON, inline samples.
• code is at https://gist.github.com/danbri/0c26bd3dedfcc66e73fb5f2b4c682e3e

from schemarama.

Possible diagnosis and fix for this not running: we're using very simple static HTTP servers that aren't sending the right media type headers for things that are in JSON (or any format for that matter).

I tried

    $.get(`tests`, (res) => { 
        let jres = $.parseJSON(res);    
        initTests(jres.tests)
    });

... in core.js line 39 and it seems to work.

Another gotcha, the demo assumes at least 3 tests will be sent from /tests, currently.

from schemarama.