This combines URLs similar to an URL join, but assumes the
base URL is the root path instead of the host.

This is useful for combining API paths with API server entry points.

appending "#debug" to the URL enables it again. Not sure if this
the best mechanism, but better than spaming the console for now.

Add anew one since this adds some default padding and I don't want to
break existing layouts by changing the normal button.

If we figure out a way to keep the layout the same without changing
the padding then we can merge things back.

Also align the mini spinner a bit better with text

These allow linking multiple AbortControllers and ceate a timeout abort signal.

For example in case you want to abort a fetch in case

(1) the UI element gets removed
(2) a newer request replacing this one gets started
(3) a timeout happens because the fetch takes too long

createLinkedAbortController() allows merging multiple signals into one
and createTimeoutAbortSignal() allows creating a singal that auto aborts
after some time passes.

This generalizes the features of the events module and should replace it in the long run.

It allows simple pub/sub and retained events without a centralized instance.

When specifying a package for code splitting, rollup requires the
packages to have a valid entry point for some reason.

Add an empty one.