Investigate slow wasm ui startup

[wirew0rm]

Loading the wasm ui from the service (especially if it is not running on localhost) takes significant amount of time while the console and network monitor show repeated requests for the main javascript file.

From the error messages it seems that each browser working thread starts up its own request for the javascript it is supposed to run, overwhelming the httplib based rest backend of the service.

Searching for the messages brings up some threads, but the most helpful i could find was this one suggesting to update emscripten.
emscripten-core/emscripten#15548 (comment)