A better fetch with proper errors

[WebReflection]

This MR supersedes #145 by actually improving the underlying library.

It's true that it doesn't reduce much bloat but while writing the other MR I've realized what a "burden" it would be to remember that when fetch fails we want to throw an error (or unhandled Promise rejection) so latest @webreflection/fetch does that, it's 100% code covered, including errors and logs, so I believe it's better to just keep that updated instead of manually searching for all possible fetch in the wild.

/cc @ntoll ... thoughts?

[WebReflection]

example of how things gracefully fail with meaningful errors (there it's a json() that is not actually a json, other tests check against status code and whatnot)