remove the fireplace-specific debug page from commonplace

- it includes buckets/mobilenetwork stuff so it's incompatible with other commonplace projects
- fireplace is only commonplace project that would be used mainly on mobile
- if someone wants to clear localstorage or something, that can be done in-browser
- probably can't do ashes anymore, but no one really does ashes outside of fireplace. to reproduce errors, we can just try it in browser
I mean model caching is available to other projects, just none of the other projects actually use it.