Chrome won't render search app components that set attributes in constructor

[derekenos]

When attempting to view the production search app in Chrome, the custom <search-app> element was present in the source but not being rendered. There were no errors reported in the console. Testing locally, I removed the type="module" from the search app import in head.html, reloaded and saw Chrome complain in the console:

Uncaught DOMException: Failed to construct 'CustomElement': The result must not have attributes

See: https://stackoverflow.com/questions/43836886/failed-to-construct-customelement-error-when-javascript-file-is-placed-in-head

Moving the script import from head.html to foot.html appears to fix the problem for now, but we should modify the search app to comply with the guidelines outlined here: https://html.spec.whatwg.org/multipage/custom-elements.html#custom-element-conformance