Add config file for specification of standard form options

[jsheunis]

json-editor form options are specified in javascript upon creation of a JSONEditor instance, e.g.:

config = {
      ajax: false,
      schema: my_schema_object,
      theme: 'psyinf',
      iconlib: 'fontawesome5',
      object_layout: 'table',
      disable_edit_json: true,
      disable_properties: true,
      disable_collapse: true,
      remove_empty_properties: true,
      show_errors: 'interaction',
      show_opt_in: false,
      compact: false,
    }
    const form_element = document.getElementById("formeditor");
    editor = new JSONEditor(form_element, config);

To facilitate the use of a template-like "form renderer", it would be ideal for form implementers (not form users) to not have to make any custom changes to the code. The ideal process would be:

• create a config.json file with the configuration options for JSONEditor
• provide a link to the json-schema document, or the document itself
• have a command line api to do something like create-form -c config.json -s schema.json, which then creates all code and assets needed for a self-contained web-based form
• serve the resulting codebase online

Another ideal process could be:

• have a single online form rendered, already served with all required code and assets
• enter/upload the config and schema in this site
• the site renders the form in-place

Although, I have to admit I am not certain about the security implications of the latter option.