[Mitranim]

We need a standard destructor interface instead of choosing a different word every time. Cancel, close, destroy, drop, unmount, they do the same thing. If we settled on ONE destructor interface, we could have automatic resource management. [1] I use `deinit` in all my libraries, as it seems to be the most neutral word appropriate for every case.

`arrive` — no particular reason. It's one "errback" method rather than two methods like `resolve/reject`, so it needs to have a neutral tone. Not too happy with it, better suggestions are welcome.

[1] Basic implementation of automatic resource management in JS: https://mitranim.com/espo/#-agent-value-