Improve user experience in case of startup issues #363
Description
During startup of the emscripten version of the UI, due to the diversity in runtime environments (browser versions, network, cpu-load, browser-plugins) we can observe sporadic issues:
- web-assembly version mismatches or failure to load the wasm binary -> page stays in the spinner state
- failure to load the list of dashboards or the requested dashboard -> built-in default dashboard gets started, which is unexpected for users since it shows mock data and users have to realize that they are not looking at actual data
Proposed improvements:
- Add some text to the load screen which instructs to reload the page in a new tab circumventing the browser cache (similar to what is shown on pages doing an automatic redirect after some time)
- Add a setting (Build or runtime?) that controls whether the built-in dashboard source gets added.
-> if the requested dashboard cannot be fetched from the server, a blank page should be shown (same as is the case with an invalid dashboard yml). Long term the Dashboard selection page should be shown, but I don't think it's in a state that should be presented by default right now.
-> ☑️ fixed in Bump GR4 #360, there is now a build-time option to disable the builtin demo dashboards in the UI