Consider removing the default implementation of the Worker trait's 'name_of_resource' function

[thepackett]

Very simple feature request, the title largely says it all.

The current default implementation of the Worker trait's 'name_of_resource' function simply returns 'main.js'.
Since it is extremely unlikely that a worker's required resource file happens to be called main.js, and since there is no other sensible default, I would propose to remove the default implementation and thus require the function to be implemented manually.

This has the benefit of bringing it to a user's attention when implementing the Worker trait as something that requires attention, rather than sweeping it under the rug and almost guaranteeing and bug down the line.

I would expect this to change to make the api a bit more clear, especially for people learning to use yew like myself.
I also doubt that many projects use the current default implementation, but I may be mistaken.

[futursolo]

This will be removed after #2773 which will migrate to the newer gloo-worker API.
This is currently blocked by an upstream PR in gloo-worker.