[newfeature]: implement concept lib loading on GUI

When using the web interface, huggingface concept lib concepts such as `<old-brno>` or `<poolrooms>` do not get downloaded/replaced.

To debug/reproduce: put a breakpoint in `triggers_to_concepts()` and `concepts_to_triggers()`, note that neither are called when using the web UI to invoke `a dog in <old-brno>`
