Instead if a task is used from inside a request
you MUST call kore_task_bind_request() on it.
This way we can move forward for tasks that
don't belong to page handlers.
Also, some bug fixes for removing http_requests
that are indeed linked to a currently running task.
Tasks are now assigned to available threads instead
of a global task list.
You can now pass messages between your page handler
and the created task using the kore_task_channel_*
functions.
Only one task per time can be assigned to a request
but I feel this is probably a bad design choice.
Preferably we'd want to be able to start tasks
regardless of being in a page handler or not,
this not only ads flexibility but seems like
a better choice overall as it opens a lot more
possibilities about how tasks can be used.