Global toastify options

[PVince81]

Make it possible to set toastify options globally so that one doens't need to pass in the same options everywhere.

One use case would be to pass in an offset for apps that have a top bar, see https://github.com/nextcloud/spreed/pull/5794 or even to switch to bottom aligned notifications for some layouts.

[ChristophWurst]

I'm fine if it's something stateless without side effects, e.g. like we did with https://github.com/nextcloud/nextcloud-logger#usage.

[nickvergessen]

I'm fine if it's something stateless without side effects, e.g. like we did with https://github.com/nextcloud/nextcloud-logger#usage.

That will not quite cut it for Talk at least:

• Talk allows to "fullscreen" the Talk area (video call area + right sidebar)
• If that is done, any showError() from viewer, editors, sharing, talk, deck, tasks and other apps that integrate with the Talk UI, must not be mounted on body or whatever, but Talk needs to be able to define this, without the other apps having to adjust their code.